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ATTACK ON OFFSHORE TARGETS IN THE EXCLUSIVE ECONOMIC ZONE AND IMPLICATIONS FOR NATO COLLECTIVE DEFENCE

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ATTACK ON OFFSHORE TARGETS IN THE EXCLUSIVE ECONOMIC ZONE AND IMPLICATIONS FOR NATO COLLECTIVE DEFENCE

THE CASE OF ROMANIA IN THE BLACK SEA

AUTHORS:

Admiral (rtr) PhD. Aurel POPA-President of the Maritime Security Forum

Associate Professor PhD. Cristina Elena POPA TACHE – expert at the Maritime Security Forum

Art. 5. ….“An armed attack against one or more of the Parties in Europe or North America shall be considered an attack against all……” — The key element is the phrase “against a Party” — not “against the territory”.

Abstract

The growing strategic importance of offshore infrastructure has created a new intersection between the law of the sea, international law regarding the use of force, and collective security regimes. Although installations located in the Exclusive Economic Zone are subject to the jurisdiction and regulations of the coastal state, they increasingly constitute critical assets for national and regional energy and economic security. If the waters in which they are located are directly or indirectly affected by an armed conflict, security issues arise. The article examines whether an attack on offshore installations situated in Romania’s Exclusive Economic Zone in the Black Sea could be legally and politically classified as an armed attack against Romania, with the potential to trigger NATO’s collective defence mechanisms. By integrating the legal regime of the Exclusive Economic Zone under UNCLOS, the definition of “armed attack” provided in Article 51 of the UN Charter, and the interpretive framework of Articles 5 and 6 of the North Atlantic Treaty, the study demonstrates that contemporary security realities require an evolutionary and functional interpretation of collective defence obligations. Special attention is given to hybrid operations and covert sabotage against submarine infrastructure, the challenges of attribution, as well as the increasingly recognised importance, within NATO, of critical submarine infrastructure as a component of allied security. Against this backdrop, a strong national security strategy is essential. The article also identifies public policy priorities for Romania regarding forensic preparedness, the integration of maritime surveillance, and the planning of allied infrastructure protection in the Black Sea region.

Keywords: Exclusive Economic Zone; offshore installations; law of the sea; UNCLOS; critical infrastructure; hybrid

  1. Introduction

The article starts from the main feature of the NATO treaty, namely that it is a general framework for collective security, not a detailed legal instrument for operational regulation. In its 14 articles, it establishes principles, obligations and institutional mechanisms, rather than technical rules or tactical procedures.Article 3 confirms this by stating that: “To fulfil more effectively the objectives of this Treaty, the Parties, separately or jointly, through continuous self-help and mutual support, will maintain and develop their individual and collective capacity to resist armed attack.” We begin our analysis from the objective reality that the NATO Treaty is a legal framework for collective security, which does not explicitly regulate modern operational areas such as offshore, cyber and space, leaving their development to subsequent strategic documents.

The contemporary international legal order is undergoing a metamorphosis driven by the technological, energy and geopolitical transformations of recent decades[1] . While the law of the sea and collective security evolved relatively separately in the second half of the 20th century, the beginning of the 21st century marks an inevitable convergence between these two branches [2] . The growing dependence of states on offshore infrastructure, whether energy, digital or logistical, has transformed maritime areas beyond national territory into objects of vital strategic interest. This reality has led to a conceptual confrontation between the non-territorial nature of the Exclusive Economic Zone and the need for effective protection of the fundamental interests of coastal states.

The Exclusive Economic Zone (EEZ), legally established by the 1982 United Nations Convention on the Law of the Sea, was originally conceived as a compromise between freedom of the seas and the extensive sovereignty claims of coastal states over marine resources.[3] Over the past two decades, however, the EEZ has become an area of intensive industrial infrastructure: hydrocarbon exploitation platforms, liquefied natural gas terminals, offshore wind farms, global submarine communications cables and cross-border pipelines. Therefore, although the EEZ is not part of the state’s territory, it concentrates assets that are essential for the functioning of the economy, energy security and digital resilience. Article 21 of UNCLOS provides the following in the section on Laws and regulations of the coastal state relating to innocent passage: “1. The coastal State may adopt, in accordance with the provisions of this Convention and other rules of international law, laws and regulations relating to innocent passage in its territorial sea, which may concern the following matters: (a) the safety of navigation and the regulation of maritime traffic; (b) the protection of navigation aids and other equipment or installations; (c) the protection of cables and pipelines; (d) the conservation of the living resources of the sea; (e) the prevention of violations of the laws and regulations of the coastal State relating to fishing; f) preservation of the coastal State’s environment and prevention, reduction and control of pollution; g) marine scientific research and hydrographic surveys; h) prevention of violations of the coastal State’s customs, fiscal, immigration or sanitary laws and regulations. These international provisions give the coastal or riparian state the possibility to take military action, especially if they are linked to the fact that innocent passage is considered as such only as long as it does not prejudice the peace, good order or security of the coastal state, as provided for in Article 19[4] .

However, despite the provisions of UNCLOS, the transformation of international conflict has produced an operational continuum between peace and war, characterised by hybrid operations, covert sabotage, cyber attacks and the use of proxy actors.[5] These instruments allow critical infrastructure to be seriously damaged without explicitly resorting to conventional military force and without the state officially assuming responsibility. From this perspective, offshore infrastructures are ideal targets because they are technically vulnerable, difficult to monitor continuously and located in a legal space between national jurisdiction and international freedom.

Recent incidents in the Euro-Atlantic area confirm the operational nature of this vulnerability. The sabotage of the Nord Stream pipelines in September 2022 not only caused significant economic losses, but also a strategic shock to the security of European submarine energy infrastructure.[6] The damage to the Balticconnector pipeline between Finland and Estonia in 2023 demonstrated the persistence of risks and the difficulty of quickly assigning responsibility. Added to this are the repeated attacks on Ukrainian offshore and coastal energy infrastructure in the Black Sea, which have confirmed the integration of this type of target into contemporary conflicts.

For Romania, these developments are not just external case studies. The discovery of hydrocarbons in the Neptun Deep perimeter and the development of related offshore infrastructure place the Romanian state in a new category of strategic maritime vulnerability.[7] The accelerated militarisation of Crimea after 2014 and Russia’s naval projection in the Black Sea have led to a reconfiguration of the regional balance of power, in which Romanian offshore infrastructure implicitly becomes a potential target for strategic coercion.

In this context, the central question of this article arises: can an attack on a Romanian offshore target located in the Exclusive Economic Zone be classified as an “armed attack against Romania” within the meaning of the UN Charter and the North Atlantic Treaty, with the potential to activate NATO’s collective defence mechanisms?

  • The legal status of offshore targets in the Exclusive Economic Zone

 In legal and strategic terminology and in NATO practice, “offshore targets” refer to facilities and infrastructure located in the marine environment, outside the land territory of the state, particularly in the Exclusive Economic Zone (EEZ), which have economic, energy, technological or strategic value. The operational definition, if we are to identify it, is as follows: offshore facilities are understood to mean those artificial installations, infrastructure and equipment located at sea or on the seabed, used for the exploitation of resources, the production or transport of energy, communications or surveillance, under the jurisdiction of the coastal state in accordance with Article 56 of UNCLOS[8] .

The issue is particularly complex because it involves three distinct levels of regulation: the law of the sea, which establishes the legal status of the EEZ and offshore installations; the use of force and self-defence, which defines the concept of “armed attack”; and NATO collective security, which conditions the allied response on the interpretation of Articles 5 and 6 of the North Atlantic Treaty.

None of these regimes provides an explicit response to attacks on modern offshore infrastructure. This regulatory gap requires an interpretation adapted to new technological and strategic realities.

At the same time, it should be emphasised that NATO mechanisms do not operate automatically on the basis of a simple legal finding. The activation of Article 5 is a collective political decision, dependent on the consensus of member states and a joint assessment of the seriousness and attribution of the incident. The term “activation” means nothing more than what we said at the beginning of the introduction, namely that it activates the development of subsequent, targeted strategies for the most pressing defence and security issues.

 Therefore, legal analysis must be complemented by an understanding of the political and strategic dynamics of the Alliance. The objective of this article is to provide a coherent analytical framework for assessing situations of attack on Romanian offshore targets, combining interpretation of UNCLOS rules on jurisdiction over offshore installations; the standards for qualifying an “armed attack” in international law; the interpretation of NATO Articles 5 and 6 in relation to non-territorial maritime spaces; the operational lessons of recent incidents involving European submarine infrastructure. Through this method, the paper aims to contribute to the clarification of an insufficiently theorised area, but one with immediate relevance for the security of Romania and NATO’s eastern flank.

2.1. The concept and legal rationale of the Exclusive Economic Zone

The concept of the Exclusive Economic Zone emerged in response to the expansion of states’ claims to marine resources in the 1960s and 1970s. In the absence of uniform regulations, coastal states (as defined in Romanian legislation) began to unilaterally proclaim extended jurisdictions over fishing and underwater resources, generating global legal uncertainty. UNCLOS (1982) codified a compromise whereby the coastal state does not obtain full territorial sovereignty over the EEZ, but receives functional sovereign rights over resources and certain economic activities.

Article 55 of UNCLOS defines the EEZ as “an area beyond and adjacent to the territorial sea under a special legal regime”. Article 56 confers on the coastal state sovereign rights for the exploration and exploitation of natural resources, as well as jurisdiction over artificial installations, scientific research and environmental protection.[9]

This is how international law creates a dual regime that lacks territorial sovereignty but is subject to exclusive functional jurisdiction.

This distinction is fundamental to the analysis of security, as the state does not own the territory but has exclusive competence over economic activities and installed infrastructure.

2.2. The status of offshore installations in maritime law

Article 60 of UNCLOS explicitly regulates artificial islands, installations and structures. It provides that the coastal state has the exclusive right to construct and authorise installations; exercises exclusive jurisdiction over them; may establish safety zones around them; installations do not have the status of islands and do not generate territorial sea.[10]

Therefore, an offshore platform is a distinct legal object because it is not territory, but is entirely under the jurisdiction of the coastal state, which refers to administrative, fiscal, security, criminal and physical protection powers.

The doctrine has emphasised that exclusive jurisdiction over offshore installations creates a ‘functional quasi-territoriality’ sufficient to trigger international responsibility in the event of an external attack.¹¹

2.3. Offshore infrastructure and the evolution of the concept of critical infrastructure

After 2001, the notion of critical infrastructure became central to Western security strategies. NATO and the European Union identified energy, communications and transport as sectors vital to the functioning of modern states.[11]

In recent NATO documents, offshore energy infrastructure and submarine cables are explicitly mentioned as strategic vulnerabilities. The NATO 2022 Strategy states that “the protection of critical infrastructure, including submarine infrastructure, is essential for collective resilience.”[12]

Political classification influences legal interpretation in the sense that if an offshore target is recognised as critical national and allied infrastructure, an attack on it takes on strategic significance equivalent to an attack on a vital land target.

2.4. The case of Romania: the specifics of the EEZ in the Black Sea

Romania exercises jurisdiction over a significant EEZ in the Black Sea, established by delimitation agreements and the jurisprudence of the International Court of Justice in the case of Romania v. Ukraine (2009).[13]

This EEZ includes developing offshore energy areas, which will become central elements of national and regional energy security. Therefore, the related infrastructure acquires a status of major strategic interest, amplifying the legal and security relevance of its protection.

3.  Attacks on offshore targets and the use of force in international law

3.1.  Prohibition of the use of force and the exception of self-defence

Article 2(4) of the UN Charter enshrines the general principle of the prohibition of the use of force in international relations. The only exceptions are authorisation by the Security Council and the inherent right of self-defence in the event of an armed attack (Article 51).[14]

Therefore, in order to justify the use of force in defence of an offshore target under attack, it must be established whether the incident constitutes an ‘armed attack’ within the meaning of the Charter.

3.2. Defining the threshold of an “armed attack”

The jurisprudence of the International Court of Justice has established that an “armed attack” is the most serious form of the use of force. In the Nicaragua case, the Court specified that not every violent incident or act of sabotage reaches this threshold.[15] Applied to offshore infrastructure, the assessment criteria are the extent of physical destruction; human casualties; systemic economic effects; environmental impact; and demonstrable hostile intent.

Minor sabotage or accidental damage would not meet the threshold. In contrast, the deliberate destruction of a major energy platform or vital pipeline could qualify as an armed attack.

3.3.  Hybrid attacks and clandestine sabotage

Contemporary conflicts have given rise to forms of aggression that avoid direct military confrontation. Underwater sabotage, the use of maritime drones or covert operations allow offshore infrastructure to be damaged without leaving a classic military signature.

Although these actions appear to temporarily avoid formal legal classification, prevailing doctrine accepts that deliberate sabotage of critical infrastructure may constitute an armed attack if the effects are serious[16] .

3.4. Cyber attacks on offshore infrastructure

The digitisation of offshore platforms makes them vulnerable to cyber attacks on SCADA and industrial control systems. The Tallinn Manual 2.0 confirms that a cyber attack can constitute an armed attack if it produces serious physical effects.

Thus, a cyber attack that causes a platform to explode or a prolonged shutdown of energy production may meet the legal threshold for self-defence.

3.5. The problem of attribution

In international law, state responsibility for the actions of non-state actors arises when they act under state control or direction.[17]

In hybrid maritime operations, attribution is often difficult. However, in NATO practice, political decisions are based on joint intelligence assessments, not exclusively on strict judicial standards of proof.

Therefore, the impossibility of immediate public attribution does not preclude an allied response, but may initially lead to consultations under Article 4 of NATO.

4.  The historical rationale for Articles 5 and 6 and the limitations of the original text

The North Atlantic Treaty was negotiated and signed in 1949 in a strategic context that was profoundly different from the current one. The main concern of the founding states was to defend European territory against massive conventional aggression. Consequently, the wording of Articles 5 and 6 reflects the technological and operational realities of the post-war period, when offshore industrial infrastructure was not yet a key component of national security.

Article 5[18] enshrines the principle of collective defence, stating that an armed attack against one or more Parties is considered an attack against all and triggers the exercise of the right to individual or collective self-defence. The text avoids explicitly limiting the notion of “attack against a Party” to national territory, but leaves this delimitation implicit in Article 6, which defines the geographical area in which attacks can trigger the mechanism.

Article 6 specifies that, for the purposes of Article 5, an armed attack is considered to be one directed against the territory of any of the Parties in Europe or North America, against the French departments of Algeria (a clause that has become obsolete), against the armed forces, ships or aircraft of the Parties in or over these territories or in the Mediterranean Sea or the North Atlantic north of the Tropic of Cancer.[19]

The wording of Article 6 reveals two key features. Firstly, it was designed to cover exclusively the territory, forces and conventional military assets of the Member States. Secondly, it does not explicitly mention maritime areas beyond territorial waters or fixed offshore installations. This omission is not a deliberate exclusion, but simply reflects the fact that such strategically relevant infrastructure did not exist in 1949.

The reality raises the central question: can Article 6 be interpreted in an evolutionary manner to include modern offshore targets located in the Exclusive Economic Zone? Or, on the contrary, do the geographical limits of the original text explicitly exclude these targets from the protection of Article 5?

4.2. Historical interpretation versus evolutionary interpretation of the Treaty

In treaty law, the 1969 Vienna Convention enshrines the principle of interpretation according to the ordinary meaning of the terms, in the context and light of the object and purpose of the treaty.[20] This method allows for evolutionary interpretations when the factual realities have changed substantially since the time of drafting.

Applied to the North Atlantic Treaty, its object and purpose is the collective defence of the security of the member states. In 1949, the security of states was associated almost exclusively with territorial integrity and military survival. Today, the security of states is inextricably linked to energy, digital and economic security. Offshore infrastructure, although located in non-territorial areas, is an integral part of this extended security.

A strictly literal interpretation of Article 6 would lead to the conclusion that only attacks on territory or military forces can trigger Article 5, excluding offshore infrastructure in the EEZ. However, such a reading would create an obvious protection gap and would contravene the purpose of the treaty, which is to prevent aggression through collective deterrence.

Contemporary doctrine favours a functional interpretation of security treaties, in which protection extends to the essential interests of states, even if these materialise in new legal spaces[21] . The precedent of invoking Article 5 after the attacks of 11 September 2001 demonstrates NATO’s ability to interpret the notion of ‘armed attack’ and ‘attack against a Party’ flexibly, adapting it to non-territorial and non-state threats.

4.3. NATO practice and the emergence of the concept of functional security

After the Cold War, NATO gradually expanded its security agenda beyond traditional territorial defence. The Strategic Concepts adopted in 2010 and 2022 and the declarations of recent summits have enshrined the recognition of hybrid, cyber and critical infrastructure threats.[22]

Official NATO documents explicitly state that cyber or hybrid attacks may, in certain circumstances, trigger Article 5. Although there is still no explicit statement on offshore infrastructure, documents on the protection of critical submarine infrastructure place these objectives at the centre of allied security concerns.[23]

The evolution points to the development of a concept of ‘functional security’, in which targets essential to the functioning of states are treated as extensions of territorial security, even if they are located in non-territorial spaces.

4.4.  Armed forces, ships and aircraft versus fixed installations

Article 6 explicitly refers to attacks against the armed forces, ships and aircraft of Member States, whether they are on national territory or in certain maritime areas. This provision demonstrates that the treaty does not limit protection exclusively to territory, but extends it to strategic assets outside it.

By legal analogy, if ships and aircraft of Member States on international missions can benefit from the protection of Article 5, it is reasonable to argue that offshore installations under the exclusive jurisdiction of the state and serving vital national interests can also fall under the same functional logic of protection.

We are considering an analogy that is not yet explicitly established in NATO case law or declarative practice, but is increasingly present in strategic literature and allied internal planning on critical infrastructure protection[24] .

Whatever the interpretation, this does not in any way exclude the imperative of developing a Romanian national security strategy for the Black Sea[25] .

4.5. The political threshold of allied consensus

Even if the legal interpretation allows offshore targets to be included in the scope of Article 5, the actual decision rests with the North Atlantic Council and requires unanimity among member states. This political dimension is essential to understanding the collective defence mechanism.

In NATO practice, there is a preference for gradual escalation: first consultations under Article 4, then reassurance measures, preventive deployments and sanctions, before any formal invocation of Article 5.[26]

For an attack on an offshore target, allied consensus will depend on the severity of the effects, the quality of attribution and the perception of systemic risk to allied security. Thus, legal analysis must be integrated into a strategy of evidentiary preparation and strategic communication that allows this consensus to be built. As recently stated in doctrine, a high degree of dependence on strategic allies leads to defence risks, as it makes it difficult to take the most rapid measures[27] .

 5. Lessons from recent incidents affecting European submarine infrastructure

5.1. The Nord Stream sabotage as a strategic turning point

The explosion of the Nord Stream 1 and 2 pipelines in September 2022 was the first documented case of deliberate destruction of submarine energy infrastructure of continental importance. Although official investigations have not publicly identified the perpetrator, most strategic analyses have concluded that the operation required advanced state capabilities, ruling out autonomous non-state actors.

The impact of the incident was manifold. Economically, it eliminated a primary route for Europe’s energy supply. Ecologically, it produced one of the largest accidental emissions of methane into the atmosphere. Strategically, it demonstrated that submarine energy infrastructure can be neutralised through clandestine operations without automatically triggering open conflict.

The reaction of NATO and the European Union was one of political condemnation, intensified maritime surveillance and accelerated programmes to protect critical submarine infrastructure.[28] However, neither NATO nor the EU classified the incident as an armed attack in the sense of collective defence, mainly due to the lack of an indisputable public attribution.

5.2. The Balticconnector incident and persistent vulnerability

In October 2023, the Balticconnector pipeline between Finland and Estonia was damaged under suspicious circumstances. The Finnish investigation determined that the damage was not accidental, but did not officially attribute responsibility to any state. The incident had limited operational effects, but reinforced the perception of the vulnerability of Northern European submarine infrastructure.

The allied response included stepping up NATO’s maritime presence in the Baltic Sea and setting up mechanisms for rapid exchange of information on underwater threats.[29] This response shows NATO’s preference for preventive and resilience measures over any formal legal classification of the incident as an armed attack.

5.3. Operational lessons for the Black Sea

The Black Sea presents a much more contested security environment than the Baltic Sea. Russian military presence, the use of maritime drones, mine laying and attacks on Ukrainian infrastructure demonstrate that offshore sabotage is already part of the regional operational repertoire.

In this context, Romanian offshore infrastructure may be a potential target for strategic coercion, especially in scenarios of controlled escalation below the threshold of open conflict. The central lesson of the Northern European incidents is that the lack of a clear legal attribution and qualification framework delays collective response, leaving the affected state in a position of temporary vulnerability.

In response to these incidents, NATO created the Critical Undersea Infrastructure Coordination Cell in 2023, a structure dedicated to monitoring, risk analysis and coordinating the response to threats to undersea infrastructure.[30]

The initiative marks the official recognition that offshore infrastructure is an integral part of collective security. Even if there is not yet an explicit doctrine on the application of Article 5 for attacks on offshore facilities, their integration into allied operational planning is a decisive step towards a functional interpretation of the treaty.

6. Legal and strategic implications for Romania in the Black Sea

6.1. Particularities of Romania’s position in the Black Sea security mechanism

After 2014, the Black Sea region became one of the main areas of strategic friction between the Russian Federation and the Euro-Atlantic community. The annexation of Crimea, the militarisation of the peninsula and its transformation into a naval, air and missile projection platform have profoundly altered the regional balance of power.[31] For Romania, a coastal state and NATO member on the eastern flank of the Alliance, this transformation has created a situation of direct strategic exposure.

At the same time, the discovery and development of Romanian offshore energy resources have introduced an additional economic and security dimension. The Neptun Deep, Midia and other concessions in the Romanian EEZ will generate, over the next decade, a significant increase in domestic gas production, investment and Romania’s integration as a regional energy security provider.[32] This perspective gives Romanian offshore infrastructure a strategic value that goes beyond strictly national interests, as it is relevant to the energy resilience of the European Union and NATO.

In this context, any attack or sabotage on Romanian offshore facilities would cause both major direct economic losses and a systemic effect on NATO’s credibility to protect critical infrastructure on its eastern flank. Therefore, the issue of the legal and operational protection of these objectives becomes a matter of collective security, not exclusively national security.

6.2. National legal framework and integration into international law

Romania has incorporated the provisions of UNCLOS on EEZs and jurisdiction over offshore installations into its domestic legislation. The law on the delimitation of maritime spaces and regulations on the exploitation of offshore resources enshrine the Romanian state’s authority to authorise, supervise and protect these installations.

Romania has included energy and digital infrastructure in the category of critical national infrastructure, subject to special protection and business continuity planning regimes.[33] This is an internationally relevant domestic classification, as it demonstrates that offshore facilities are fundamental interests of the state, the impairment of which could have serious consequences for national security.

In the event of an attack, Romania could invoke three legal bases simultaneously: exclusive jurisdiction over the facility under UNCLOS, the right to self-defence under Article 51 of the UN Charter, and the consultation and collective defence mechanisms of the NATO Treaty. The synergy of these three legal levels strengthens Romania’s position in the event of a crisis[34] .

6.3. Assigning strategic priority

One of the key lessons of the Nord Stream and Balticconnector incidents is that the absence of rapid and credible attribution delays collective response and creates room for strategic ambiguity. For Romania, anticipatory evidentiary preparation is essential. This involves developing national underwater monitoring capabilities, integrating satellite and AIS data, cooperating with NATO maritime intelligence structures, and establishing pre-agreed protocols for collecting and preserving technical evidence in the event of an offshore incident . In this way, Romania can quickly provide its allies with a solid factual basis for a joint assessment of attribution.

The evidentiary dimension is not purely technical, but has direct political implications. Allied consensus on any collective action, including the possible invocation of Article 5, will depend on the credibility of the evidence presented. Advance preparation in this area thus becomes a central element of deterrence.

6.4.  Romanian offshore infrastructure as an allied asset

An important development in recent NATO doctrine is the treatment of certain critical national infrastructures as assets of allied interest. Transatlantic submarine cables, strategic pipelines and regional energy hubs are already included in allied protection planning.

As Romanian offshore infrastructure becomes part of European energy security, it can be progressively classified in this category of “allied assets”. This reclassification reinforces the argument that an attack on them is not just a bilateral issue between Romania and the aggressor, but a matter of collective security.

7. Operational scenarios and response options within NATO

7.1. Scenario of clandestine sabotage with limited effects

In the first scenario, a Romanian offshore facility suffers deliberate damage caused by clandestine underwater means, with moderate economic effects and no casualties. The initial attribution is uncertain, and the aggressor does not claim responsibility for the action.

In such a situation, the legal threshold of “ rmed attack ” could be contested, and the activation of Article 5 would be unlikely. However, Romania would have grounds to invoke Article 4 of NATO for consultations, request intelligence and surveillance support, and initiate joint investigations. NATO could respond by stepping up its maritime presence, providing technical support for the investigation, and taking regional reassurance measures. This response would send a deterrent signal without direct escalation, while keeping open the option of further measures if the evidence of attribution is strengthened.

7.2. Scenario of a deliberate attack with major destruction

In a second scenario, a strategically important energy platform is destroyed by a kinetic or cyber attack, causing massive economic losses, widespread pollution and possibly human casualties. Technical investigations and allied intelligence indicate the involvement of a hostile state[35] .

In this scenario, the criteria for the severity of an “armed attack” would be met. Romania could invoke its right to self-defence and request that the North Atlantic Council be convened to assess the activation of Article 5. The final decision would depend on allied political consensus, but the legal basis would be solid.

Even if Article 5 were invoked, the allied response would not automatically be a military offensive. It could include additional defensive deployments, intensive naval patrols, defensive cyber operations, and coordinated economic and diplomatic measures.

7.3. Scenario of an attack in the context of open regional conflict

In the event of an expansion of the Russian-Ukrainian conflict or a direct escalation in the Black Sea, Romanian offshore infrastructure could become a collateral or deliberate target in a context of wider hostilities.

In such a situation, the legal classification would be clearer, and the activation of collective defence mechanisms would become part of NATO’s overall operational planning for the eastern flank. The protection of offshore infrastructure would be integrated into allied maritime and air missions, and the response would be militarily integrated ( ). With regard to deterrence through resilience and allied visibility, in all scenarios, the central element remains deterrence. A technically well-protected offshore target, continuously monitored and integrated into the allied maritime situation architecture, significantly reduces the attractiveness of a clandestine attack.

The regular presence of NATO ships in the vicinity of critical infrastructure, joint exercises to protect offshore installations, and their integration into regional defence plans increase the perceived costs of aggression and contribute to strategic stability.

8. Setting up a NATO agenda for offshore infrastructure protection: from legal ambiguity to collective security commitment

8.1. The reality of a strategic governance vacuum

The previous analysis has shown that offshore installations located in the Exclusive Economic Zone of NATO member states occupy a hybrid legal space. They are not part of national territory in the strict sense, but are under the exclusive jurisdiction of the coastal state; they are not explicitly mentioned in Article 6 of the North Atlantic Treaty, but their destruction can have systemic effects comparable to an attack on critical land-based infrastructure. This configuration creates a governance vacuum in the collective defence architecture. Although recent NATO policy documents recognise the importance of submarine and offshore infrastructure, there is still no formalised doctrine or summit-level guidance specifying the conditions under which an attack on these facilities could trigger collective defence mechanisms.

The absence of explicit clarification creates multiple strategic risks. It can weaken deterrence by giving potential adversaries room for manoeuvre below the threshold of an assured allied response. It can delay the formation of political consensus in crisis situations, particularly when attribution is difficult. And it can amplify the vulnerability of states on the Alliance’s maritime flanks, which are forced to manage the initial phase of an incident primarily through national means. Closing this governance gap therefore becomes not only a necessity for legal consistency, but also a condition for the credibility of NATO’s deterrence. In this situation, soft law can mitigate the risks of the absence of hard law regulations, provided that the most appropriate ones are transformed into hard law within a short period of time[36] .

8.2.  Political recognition of offshore infrastructure as collective security assets

The first necessary step is explicit political recognition at summit level that offshore energy and digital infrastructure under the jurisdiction of member states are assets of interest to collective security. Such recognition does not require a formal amendment to the North Atlantic Treaty, especially since it is a framework international agreement. NATO practice shows that strategic-level documents – summit communiqués and Strategic Concepts – have repeatedly expanded the operational meaning of threats without amending the text of the treaty. The recognition of cyber and hybrid attacks as potential triggers for Article 5 after 2016 is a relevant precedent.

Extending this recognition to offshore infrastructure would align NATO doctrine with the contemporary realities of energy transition, maritime industrialisation and digital interdependence. For the Black Sea littoral states, especially Romania and Bulgaria, such recognition would formally integrate offshore facilities into the common calculation of allied security, transforming maritime energy projects from exclusively national objectives into components of regional resilience.

8.3. Doctrinal clarification of Articles 5 and 6 in relation to offshore installations

Political recognition must be accompanied by doctrinal clarification. NATO’s legal and planning structures should be mandated to develop an allied guidance document on collective defence and offshore infrastructure. The document would establish how Articles 5 and 6 of the North Atlantic Treaty are interpreted when hostile acts target installations located in the Exclusive Economic Zone.

Such guidance would not redefine the treaty, but would codify an evolving interpretation based on the object and purpose of collective defence. It could specify that when offshore installations are designated as critical national infrastructure and their destruction has systemic effects on the security of the state and the Alliance, an attack on them may be treated as an attack against a Party within the meaning of Article 5, subject to the political decision of the North Atlantic Council. This approach replicates the model already adopted for cyber operations, where NATO has avoided rigid legal definitions but has established political thresholds for collective response[37] .

8.4. Institutionalising offshore protection in NATO’s operational architecture

The second pillar of a coherent NATO agenda concerns operational integration. The creation of the Critical Submarine Infrastructure Coordination Cell in 2023 was an initial response to recent sabotage in European waters. However, the current mandate of this structure remains predominantly analytical and coordinating. For effective deterrence, offshore infrastructure protection must be integrated into regional defence planning, NATO maritime domain awareness systems and permanent naval missions.

We are talking about integration that is essential in the Black Sea, where Russian naval and hybrid activity is creating a contested maritime environment. Including offshore facility surveillance in the allied ISR mechanism, coordinating naval patrols with national assets, and organising joint offshore sabotage response exercises would transform political commitments into concrete operational capabilities.

8.5. Standardisation of attribution and evidentiary preparedness

Recent incidents on European submarine infrastructure have demonstrated that the main obstacle to rapid collective response is not the absence of a legal basis, but evidentiary uncertainty. Offshore sabotage deliberately exploits the ambiguity of attribution. Consequently, NATO must develop common attribution protocols and evidentiary preparedness standards for hybrid maritime incidents.

These should include harmonised procedures for preserving the underwater incident site, sharing sensor and satellite data, merging AIS information, and joint intelligence assessments. Establishing pre-agreed technical and evidentiary benchmarks would significantly reduce the time needed to build political consensus on responsibility and response.

For Romania, investment in underwater monitoring capabilities, cooperation with allied naval forces, and integration into NATO attribution mechanisms would transform offshore vulnerability into an area of collective situational awareness.

8.6.  NATO–European Union convergence on offshore energy resilience

Offshore energy infrastructure directly supports European energy security, and NATO cannot address this area in isolation from the European Union. The EU has regulatory, financing and civil protection competencies that complement NATO’s defensive mandate. Strengthening NATO–EU coordination in the field of offshore resilience through joint planning and scenari , integrated risk assessments and synchronised crisis response protocols ensures coherence between military deterrence and civilian functional continuity.

For Romania, whose offshore facilities will supply both the domestic market and the European energy network, their simultaneous inclusion in NATO planning and EU mechanisms maximises systemic resilience.

The strategic implications for the Black Sea region start with raising the protection of offshore infrastructure to a summit priority, which would have immediate strategic consequences for the Black Sea. It would formally anchor the region in NATO’s critical infrastructure defence architecture, balancing the asymmetry created by the militarisation of Crimea through allied visibility and preparedness. At the same time, it would send a signal that hybrid maritime sabotage will not remain in a grey area of political ambiguity, but will fall under a pre-established collective response framework.

For Romania, this development would strengthen its position as a provider of energy security and a contributor to allied security on the eastern flank.

In abstract terms, making the protection of offshore infrastructure an explicit part of NATO’s agenda marks the transition from legal ambiguity to strategic credibility. By establishing common political thresholds, operational procedures and attribution standards, NATO would eliminate the strategic advantage of uncertainty exploited by adversaries. At a time when maritime sabotage and hybrid operations are increasingly replacing open aggression, the credibility of collective defence depends on the Alliance’s ability to anticipate and govern these new areas of risk.

Romania should analyse these issues and come up with relevant proposals for including these clarifications in the agenda of the next summit.

9. General conclusions

The analysis carried out in this article leads to five main conclusions.

Firstly, offshore targets located in the Exclusive Economic Zone are under the exclusive jurisdiction of the coastal state, which creates a sufficient legal link to engage international responsibility in the event of an attack.

Second, a deliberate attack with serious effects on such a facility may meet the legal threshold of an “armed attack” within the meaning of the UN Charter, allowing for the exercise of the right to self-defence.

Thirdly, Articles 5 and 6 of the North Atlantic Treaty can be interpreted evolutionarily, in light of the treaty’s purpose and new technological realities, to cover essential offshore infrastructure within the sphere of collective security interests.

Fourthly, the effective activation of Article 5 remains a political decision based on consensus, depending on the seriousness of the incident and the credibility of the attribution.

Fifthly, for Romania, the key to protecting offshore infrastructure lies in combining evidence-based preparedness, integration into NATO maritime surveillance mechanisms and the development of a national doctrine of offshore resilience.

We find ourselves in a strategic environment marked by hybrid operations and sabotage below the threshold of declared war, where the maritime security of critical infrastructure is one of the defining frontiers of Euro-Atlantic collective defence. Romania, as a coastal state and NATO member on the eastern flank, is at the forefront of this development.

Bibliography

  1. Cristina Elena Popa Tache, (2024). The regulatory frontiers of the Black Sea through the cartography of European Union law and international law – Case study: Romania’s maritime security strategy. In: Universul Juridic, no. 12/2024, pp. 75–114. Bucharest: Editura Universul Juridic. https://revista.universuljuridic.ro/wp-content/uploads/2025/01/07_Revista_Universul_Juridic_nr_12-2024_PAGINAT_BT_C_Popa.pdf .
  2. Dinstein, Yoram. War, Aggression and Self-Defence. 6th ed. Cambridge: Cambridge University Press, 2017.
  3. Francesco Casaril, Letterio Galletta, Space cybersecurity governance: assessing policies and frameworks in view of the future European space legislation, Journal of Cybersecurity, Volume 11, Issue 1, 2025, tyaf013, https://doi.org/10.1093/cybsec/tyaf013.
  4. Frank G. Hoffman, Hybrid Warfare and Challenges, Joint Force Quarterly, No. 52
  5. Georgison, Abigail. 2025. “Collective Security at the Crossroads: Analysing the UN’s Security Framework from 2005 to 2025”. Politikon: The IAPSS Journal of Political Science 26 (1). Online:4-29. https://doi.org/10.22151/politikon.60.1.
  6. Geraldo Vidigal, Evolutionary Interpretation and International Law, Journal of International Economic Law, Volume 24, Issue 1, March 2021, Pages 203–219, https://doi.org/10.1093/jiel/jgaa035.
  7. Geraldo Vidigal, Evolutionary Interpretation and International Law, Journal of International Economic Law, Volume 24, Issue 1, March 2021, Pages 203–219, https://doi.org/10.1093/jiel/jgaa035.
  8. Green, James A. “Collective Self-Defence Treaty Arrangements.” Chapter. In Collective Self-Defence in International Law, 232–75. Cambridge Studies in International and Comparative Law. Cambridge: Cambridge University Press, 2024.
  9. Green, James A. Half-title-page. In Collective Self-Defence in International Law, i–i. Cambridge Studies in International and Comparative Law. Cambridge: Cambridge University Press, 2024 and Geraldo Vidigal, Evolutionary Interpretation and International Law, Journal of International Economic Law, Volume 24, Issue 1, March 2021, Pages 203–219, https://doi.org/10.1093/jiel/jgaa035.
  10. Government of Romania, National Strategy on Critical Infrastructure Protection, 2021.
  11. Klein, Natalie, Maritime Security and the Law of the Sea, Oxford Monographs in International Law (2012; online edn, Oxford Law Pro), https://doi.org/10.1093/law/9780199668144.001.0001, accessed 14 Jan. 2026.
  12. Lindsey Guenther, Paul Musgrave, New Questions for an Old Alliance: NATO in Cyberspace and American Public Opinion, Journal of Global Security Studies, Volume 7, Issue 4, December 2022, ogac024, https://doi.org/10.1093/jogss/ogac024.
  13. Lott, Alexander. 2023. “Maritime Security in the Baltic and Japanese Straits From the Perspective of EEZ Corridors.” Ocean Development & International Law 54 (3): 327–48. doi:10.1080/00908320.2023.2265301.
  14. Maritime Delimitation in the Black Sea (Romania v Ukraine), ICJ Reports 2009.
  15. Romanian Ministry of Energy, Report on Offshore Gas Development, 2024.
  16. Romanian Ministry of Energy, Neptun Deep Development Strategy, 2023.
  17. NATO Handbook, 2022 edition.
  18. NATO Maritime Command, Enhanced Baltic Sea Patrols, 2023.
  19. NATO, Black Sea Security Assessment, 2023.
  20. NATO, Brussels Summit Communiqué, 2021.
  21. NATO, Civil Preparedness and Resilience, 2016.
  22. NATO, Critical Undersea Infrastructure Protection Policy, 2023.
  23. NATO, Establishment of the Critical Undersea Infrastructure Coordination Cell, 2023.
  24. NATO, Madrid Strategic Concept, 2022, para. 14. See more in Maria Gavouneli, Functional Jurisdiction in the Law of the Sea, Publications on Ocean Development, vol. 62 (Leiden: Brill, 2007).
  25. NATO, Press Release on Infrastructure Protection, October 2022.
  26. NATO, Press Release on Nord Stream sabotage, 29 September 2022.
  27. NATO, Strategic Concept, Madrid, 2022.
  28. Nicaragua v United States, ICJ Reports 1986, para. 191.
  29. Niccolò Lanzoni, The role of expert groups in shaping international cyberlaw: a case study of the Tallinn Manuals and international law-making, Journal of Conflict and Security Law, Volume 30, Issue 3, Winter 2025, Pages 341–358, https://doi.org/10.1093/jcsl/kraf013.
  30. Ringsberg, Jonas W., and Jeom-Kee Paik. 2025. “International Collaboration and Transformative Technologies: Reflections on Two Decades of Ships and Offshore Structures and a Decade of ICSOS.” Ships and Offshore Structures, December, 1–4. doi:10.1080/17445302.2025.2604251.
  31. Strating, Rebecca. 2023. “The Rules-Based Order as Rhetorical Entrapment: Comparing Maritime Dispute Resolution in the Indo-Pacific.” Contemporary Security Policy 44 (3): 372–409. doi:10.1080/13523260.2023.2204266.

[1] See Strating, Rebecca. 2023. “The Rules-Based Order as Rhetorical Entrapment: Comparing Maritime Dispute Resolution in the Indo-Pacific.” Contemporary Security Policy 44 (3): 372–409. doi:10.1080/13523260.2023.2204266.

[2] Georgison, Abigail. 2025. “Collective Security at the Crossroads: Analysing the UN’s Security Framework from 2005 to 2025”. Politikon: The IAPSS Journal of Political Science 26 (1). Online:4-29. https://doi.org/10.22151/politikon.60.1.

[3] UNCLOS, 1982, Art. 55–56.

[4] Article 58 of the Convention shall be taken into account: Rights and obligations of other States in the exclusive economic zone 1. In the exclusive economic zone, all States, whether coastal or landlocked, shall enjoy, under the conditions provided for in the relevant provisions of the Convention, the freedoms of navigation and overflight and of laying submarine cables and pipelines, referred to in Article 87, as well as the freedom to use the sea for other internationally lawful purposes related to the exercise of these freedoms and compatible with the other provisions of the Convention, in particular in the operation of ships, aircraft and submarine cables and pipelines. 2. The provisions of Articles 88 to 115, as well as other relevant rules of international law, shall apply to the exclusive economic zone to the extent that they are not incompatible with this Part. In exercising their rights and performing their duties under the Convention in the exclusive economic zone, States shall take due account of the rights and duties of the coastal State and shall respect the laws and regulations adopted by it in accordance with the provisions of the Convention and, to the extent that they are not incompatible with this Part, the other rules of international law. Furthermore, Article 19(2) provides that:  The passage of a foreign ship shall be considered to be prejudicial to the peace, good order or security of the coastal State if, in the territorial sea, such ship engages in any of the following activities:

(a) the threat or use of force against the sovereignty, territorial integrity or political independence of the coastal State or in any other manner inconsistent with the principles of international law embodied in the Charter of the United Nations;

b) exercising or manoeuvring with weapons of any kind;

c) gathering information to the detriment of the defence or security of the coastal State;

d) propaganda aimed at undermining the defence or security of the coastal State;

e) launching, landing on ships or embarking aircraft;

f) launching, landing or embarking military equipment;

g) embarking or disembarking goods, funds or persons contrary to the customs, fiscal, sanitary or immigration laws and regulations of the coastal State;

h) deliberate and serious pollution in violation of this Convention;

i) fishing;

j) hydrographic surveys or levies;

k) disruption of the operation of any communication system or any other equipment or installation of the riparian state;

l) any other activity not directly related to passage.

[5] Frank G. Hoffman, Hybrid Warfare and Challenges, Joint Force Quarterly, No. 52

[6] NATO, Press Release on Nord Stream sabotage, 29 September 2022.

[7] Romanian Ministry of Energy, Neptun Deep Development Strategy, 2023.

[8] For more technical and legal details, see Ringsberg, Jonas W., and Jeom-Kee Paik. 2025. “International Collaboration and Transformative Technologies: Reflections on Two Decades of Ships and Offshore Structures and a Decade of ICSOS.” Ships and Offshore Structures, December, 1–4. doi:10.1080/17445302.2025.2604251. See also Lott, Alexander. 2023. “Maritime Security in the Baltic and Japanese Straits From the Perspective of EEZ Corridors.” Ocean Development & International Law 54 (3): 327–48. doi:10.1080/00908320.2023.2265301.

[9] UNCLOS, Art. 56.

[10] UNCLOS, Art. 60.

[11] NATO, Civil Preparedness and Resilience, 2016.

[12] NATO, Madrid Strategic Concept, 2022, para. 14. See more in Maria Gavouneli, Functional Jurisdiction in the Law of the Sea, Publications on Ocean Development, vol. 62 (Leiden: Brill, 2007).

[13] Maritime Delimitation in the Black Sea (Romania v Ukraine), ICJ Reports 2009.

[14] UN Charter, Art. 2(4) and 51.

[15] Nicaragua v United States, ICJ Reports 1986, para. 191.

[16] Dinstein, Yoram. War, Aggression and Self-Defence. 6th ed. Cambridge: Cambridge University Press, 2017.

[17] NATO, Brussels Summit Communiqué, 2021.

[18] North Atlantic Treaty, Art. 5.

[19] 23North Atlantic Treaty, Art. 6.

[20] Vienna Convention on the Law of Treaties, 1969, Art. 31.

[21] The evolutionary/teleological interpretation of treaties (VCLT Art. 31) as a mechanism for accommodating change is analysed today alongside the functional application of collective security obligations to new domains (cyber, space, hybrid), when essential interests and effects of comparable gravity are at stake. Geraldo Vidigal, Evolutionary Interpretation and International Law, Journal of International Economic Law, Volume 24, Issue 1, March 2021, Pages 203–219, https://doi.org/10.1093/jiel/jgaa035 and Green, James A. “Collective Self-Defence Treaty Arrangements.” Chapter. In Collective Self-Defence in International Law, 232–75. Cambridge Studies in International and Comparative Law. Cambridge: Cambridge University Press, 2024.

[22] NATO, Strategic Concept, Madrid, 2022.

[23] NATO, Critical Undersea Infrastructure Protection Policy, 2023.

[24]  See by analogy Niccolò Lanzoni, The role of expert groups in shaping international cyberlaw: a case study of the Tallinn Manuals and international law-making, Journal of Conflict and Security Law, Volume 30, Issue 3, Winter 2025, Pages 341–358, https://doi.org/10.1093/jcsl/kraf013, Lindsey Guenther, Paul Musgrave, New Questions for an Old Alliance: NATO in Cyberspace and American Public Opinion, Journal of Global Security Studies, Volume 7, Issue 4, December 2022, ogac024, https://doi.org/10.1093/jogss/ogac024.

[25] Cristina Elena Popa Tache, (2024). The regulatory boundaries of the Black Sea through the cartography of European Union law and international law – Case study: Romania’s maritime security strategy. In: Universul Juridic, no. 12/2024, pp. 75–114. Bucharest: Editura Universul Juridic. https://revista.universuljuridic.ro/wp-content/uploads/2025/01/07_Revista_Universul_Juridic_nr_12-2024_PAGINAT_BT_C_Popa.pdf

[26] NATO Handbook, 2022 edition.

[27] Cristina Elena Popa Tache, (2024). The regulatory boundaries of the Black Sea through the cartography of European Union law and international law – Case study: Romania’s maritime security strategy. In: Universul Juridic, no. 12/2024, pp. 75–114. Bucharest: Universul Juridic Publishing House. https://revista.universuljuridic.ro/wp-content/uploads/2025/01/07_Revista_Universul_Juridic_nr_12-2024_PAGINAT_BT_C_Popa.pdf.

[28] NATO, Press Release on Infrastructure Protection, October 2022.

[29] NATO Maritime Command, Enhanced Baltic Sea Patrols, 2023.

[30] NATO, Establishment of the Critical Undersea Infrastructure Coordination Cell, 2023.

[31] NATO, Black Sea Security Assessment, 2023.

[32] Romanian Ministry of Energy, Report on Offshore Gas Development, 2024.

[33] Romanian Government, National Strategy on Critical Infrastructure Protection, 2021.

[34]  The conclusion is consistent with international law and the experience it provides. See Green, James A. Half-title-page. In Collective Self-Defence in International Law, i–i. Cambridge Studies in International and Comparative Law. Cambridge: Cambridge University Press, 2024 and Geraldo Vidigal, Evolutionary Interpretation and International Law, Journal of International Economic Law, Volume 24, Issue 1, March 2021, Pages 203–219, https://doi.org/10.1093/jiel/jgaa035.

[35] Klein, Natalie, Maritime Security and the Law of the Sea, Oxford Monographs in International Law (2012; online edn, Oxford Law Pro), https://doi.org/10.1093/law/9780199668144.001.0001, accessed 14 Jan. 2026.

[36] Geraldo Vidigal, Evolutionary Interpretation and International Law, Journal of International Economic Law, Volume 24, Issue 1, March 2021, Pages 203–219, https://doi.org/10.1093/jiel/jgaa035.

[37] Francesco Casaril, Letterio Galletta, Space cybersecurity governance: assessing policies and frameworks in view of the future European space legislation, Journal of Cybersecurity, Volume 11, Issue 1, 2025, tyaf013, https://doi.org/10.1093/cybsec/tyaf013.

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