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By: Konstantinos Deligiannis Virvos, Vito De Lucia and Jan Jakub Solski, Norwegian Centre for the Law of the Sea (NCLOS), Faculty of Law, UiT The Arctic University of Norway<\/p>\n\n\n\n
In September 2025, the United States of America (US) launched operation \u201cSouthern Spear\u201d<\/a> which, among other actions, included a blockade of oil tankers sanctioned by the US and traveling to or from Venezuela. The actions by the US during the operation (which have involved the continuous bombing of alleged \u201cnarco-boats\u201d<\/a>, the attack on Caracas and the arrest of Venezuelan President Nicolas Maduro<\/a>) are widely considered illegal (see here<\/a>, here<\/a> and here<\/a>). The present analysis focuses on the interception of oil tankers on the high seas and its implications for the law of the sea and international law more broadly.<\/p>\n\n\n\n Specifically, since December 2025, the US has intercepted several oil tankers of various flags on the basis of sanctions imposed by the US Department of Treasury<\/a>. It has claimed that the vessels were either not flying the flag of any State or were \u201cfalsely flagged.\u201d The incident that caught the most public attention<\/a> was that of the Bella 1 <\/em>(now renamed the Marinera<\/em>). The present blog post discusses first the legality of the interception of the Bella 1\/Marinera<\/em> and then explores broader questions pertaining to the freedom of navigation in the current turbulent geopolitical context and whether the incident is a signal of a possible re-ordering of the law of the sea. <\/p>\n\n\n\n On the December 20, 2025, the US Coast Guard attempted to intercept the Bella 1<\/em> in the Caribbean (presumably within the EEZ of Antigua and Barbuda<\/a>), but the vessel managed to evade capture. On December 30, the crew painted a Russian flag on the hull of the vessel, and by January 1, 2026<\/a>, the vessel had been registered with the Russian Maritime Registry of Shipping. Russia even provided the vessel with naval escorts<\/a>. Despite this, the Bella 1<\/em> was ultimately seized by the US Coast Guard, with assistance from the United Kingdom (UK)<\/a>, on January 7, 2026.<\/p>\n\n\n\n In accordance with the law of the sea, the flag State has exclusive jurisdiction over ships flying its flag, with the exceptions of the right of visit (Art. 110), the right of hot pursuit (Art. 111). The latter is not applicable in the present case since hot pursuit may only commence when the foreign ship or one of its boats is within the internal waters, the archipelagic waters, the territorial sea, the contiguous zone, or EEZ of the pursuing State. Under Article 110 UNCLOS, except where acts of interference derive from powers conferred by treaty or flag State consent, a warship may only board a foreign-flagged vessel if there is reasonable suspicion that<\/p>\n\n\n\n (a) the ship is engaged in piracy;<\/p>\n\n\n\n (b) the ship is engaged in the slave trade;<\/p>\n\n\n\n (c) the ship is engaged in unauthorized broadcasting and the flag State of the warship has jurisdiction under article 109 UNCLOS;<\/p>\n\n\n\n (d) the ship is without nationality; or<\/p>\n\n\n\n (e) though flying a foreign flag or refusing to show its flag, the ship is, in reality, of the same nationality as the warship.<\/p>\n\n\n\n While the US is not a party to the UNCLOS, it considers much of its provisions reflected in customary international law<\/a>. The US did not, at the time of the interception of the Bella 1\/Marinera<\/em>, publicly invoke any of the exceptions provided for in Art. 110 UNCLOS but undertook the actions against the vessel on the basis of unilateral sanctions against them by the US Department of Treasury<\/a>. However, unilateral sanctions cannot form the basis to exercise jurisdiction over a vessel on the high seas.<\/p>\n\n\n\n The UK, which assisted in the operation, offered arguments for the boarding and for assisting the US with the interdiction of the Marinera<\/em>. UK Defense Secretary Healey<\/a> referred to \u201cfalsely flagged\u201d vessels\u2014presumably meaning that the ship is without nationality in accordance with UNCLOS Art. 110 (1) (d), an argument that has since then been used by the US<\/a> as well. Based on the available information, it can be argued that this is the for other vessels that were intercepted as part of the same operation as for example the M Sophia<\/em><\/a>. However, this does not hold true for all vessels that were intercepted as part of operation \u201cSouthern Spear\u201d, and certainly not for the Bella 1\/ Marinera<\/em>. <\/em>Russia had repeatedly<\/a> stated<\/a> the latter vessel was flying its flag. This is a claim that is difficult to challenge under the current law of the sea and the available information showcases that the Bella 1\/ Marinera<\/em> was listed<\/a> in the relevant Russian ship database before the arrest.<\/p>\n\n\n\n And while Article 92 (1) UNCLOS states \u201cA ship may not change its flag during a voyage or while in a port of call, save in the case of a real transfer of ownership or change of registry\u201d, this provision cannot be read as providing for the total prohibition of a change of flag during a voyage since it includes the caveat of a real transfer of ownership or, importantly in this case, the change of registry.<\/p>\n\n\n\n UNCLOS Article 91 (1) provides that \u201cEvery State shall fix the conditions for the grant of its nationality to ships, for the registration of ships in its territory, and for the right to fly its flag\u201d. The same provision\u2019s last sentence adds that \u201cThere must exist a genuine link between the State and the ship\u201d. While this can be read as an additional requirement for the flag State when registering a ship, ITLOS jurisprudence has consistently stated that Article 91 (1) cannot be read as establishing criteria for other States to challenge the validity of the registration of a ship in a flag State (as stated in the M\/V \u201cSaiga\u201d (No 2) Case, <\/a>para 83, and repeated in the M\/V \u201cVirginia G\u201d Case<\/a>, paras 110-112). It could be debated, however, whether a genuine change of registry can be effectively executed online without first conducting a thorough inspection of the vessel and its associated certificates pertaining to, among other things, maritime safety and environmental protection, as mandated by SOLAS, MARPOL, and other International Maritime Organization (IMO) standards. While this gives rise to valid concerns over maritime safety and environmental protection from sub-standard vessels, it does not provide a legal foundation for asserting that a vessel is not registered in a State that consistently affirms its registration, nor does it justify the boarding of a vessel on the high seas under Art. 110 UNCLOS.<\/p>\n\n\n\n An interesting perspective is offered by Cavalcanti de Mello Filho<\/a>. He considers that in the context of the Russian dark fleet, certain flag States are \u201cunwilling\u201d to exercise control over the ships flying their flag, thus posing a danger to the public order at sea. He concludes that \u201cunwillingness to control is contrary to the duty to protect the public order at sea and thus may permit other States to exercise jurisdiction over its vessels, in the form of non-recognition of the flag State\u2019s exclusive jurisdiction. Importantly, non-recognition, thus conceived, does not challenge the international validity of a registration; rather, it denies that the flag State\u2019s exclusive jurisdiction is assertable vis-\u00e0-vis other States in respect of ships that remain outside its effective control.\u201d While his discussion of historical practice and precedent that may support this view and re-interpret the relevant ITLOS decisions is interesting, it does not alter the rights conferred to third States by virtue of Article 110 UNCLOS. Unwillingness (or inability) on the part of the flag State to exercise effective control could potentially form the basis for the exercise of extra-territorial jurisdiction by a port State. However, it cannot be equated with a loss of nationality or the right to fly the flag of a State and hence cannot form the basis for the exercise of a right of visit against such ships.<\/p>\n\n\n\n Furthermore, it must be noted that even if a ship is without nationality, the UNCLOS provides that the inspecting vessel might board it, but it remains silent on whether it can take further enforcement actions against it. A strict grammatical interpretation of the provision does not confer any further jurisdiction beyond boarding and inspecting the vessel to the interdicting State. Many commentators argue that there must exist some \u201cjurisdictional nexus between a stateless vessel an interdicting State in order to justify the seizure of the vessel\u201d (Tanaka<\/a>, p. 220 who cites Churchill and Lowe, Papastavridis, Guilfoyle, and Anderson). While it can be argued that a ship without nationality can then be subject to the jurisdiction of any other State (a position evidently supported by the UK and the US and emerging EU practice) there is no consistent practice regarding this (Tanaka<\/a>, p. 219, and also noted by Guilfoyle<\/a>, p. 704). In practice, it is common to escort the vessel to a port of the interdicting State but \u201cthe jurisdiction exercised would be limited to the purpose of inquiring as to the status of the vessel and of the persons on board and would not substitute the full scope of the jurisdiction of the flag state\u201d (Papastavridis<\/a>, p. 266).<\/p>\n\n\n\n In any case, the actions of Russia as the flag State make it evident that it considered that the change of registry of the Bella 1\/ Marinera<\/em> happened and as already noted under current law it is left to the flag State to fix the conditions to grant its nationality to ships. In light of the available information, it cannot be argued that there was reasonable ground for suspecting that the vessel was stateless at the time of boarding in order for the US to exercise the right of visit, or that further enforcement actions could occur after boarding. The fact that the Bella1\/Marinera<\/em> may have been stateless for some time (30 December to 1 January) does not mean that it was so when it was seized.<\/p>\n\n\n\n Finally, the boarding of vessels can be considered legal as part of customary jus in bello <\/em>practices of naval blockades. However, in the absence of an international armed conflict between the USA and Venezuela, the current blockade can hardly be considered legal under customary international law, as stated in the San Remo Manual<\/a>. This has led some commentators<\/a> to characterize it as a \u201cquarantine\u201d of oil tankers. Additionally, there is no relevant resolution adopted by the UN Security Council that could provide an alternative legal basis for interception of vessels on the high seas.<\/p>\n\n\n\n The legal technical question of whether the interception is lawful is in itself interesting and rather important. However, the interception may signal a broader problem, as it not only prompts reflections on the legality of the act per se, but also on a potential legal re-ordering that may have significant and far-reaching implications, and of which the interception, regardless of the conditions and motivations underpinning it, is merely a signal. These broader reflections hinge on whether this interception (and the series of interceptions that have been undertaken on the same legal reasoning) may lead to a reshaping of the legal order of the seas with special respect to one of its foundational principles, namely the freedom of navigation.<\/p>\n\n\n\n The principle of freedom of navigation, central to the law of the sea since the resolution of the battle of the books in the seventeenth century, remains central in the architecture of the law of the sea established with the 1982 Convention, and has since the late 1970\u2019s has relied heavily on the US Freedom of Navigation operations (FoNOpS) program<\/a>. Through diplomatic and operational efforts, the US has worked to counter excessive maritime claims\u2014a Sisyphean task aimed at protecting what is essentially a global common good. While these actions served US interests, they also upheld the fundamental principle of freedom of the high seas, benefiting the entire international community.<\/p>\n\n\n\n Recent US actions do not explicitly reject this principle, but they signal that such freedom may now be conditional on political will. Additionally, these actions must be read against the broader context of a significant re-orientation of US policy in its foreign relations, as indicated with extremely clarity in the new US National Security Strategy<\/a> adopted in November 2025. Therein, the current administration makes clear two points. First, the US no longer intends to bear the world on its shoulders like Atlas, that is, it has no longer any interest in bearing the costs of providing global public order services and outlines a retreat towards what the US considers its natural sphere of influence: the Western Hemisphere. Relatedly, its new national security strategy, and other strategic documents such as Executive Order of April 24, 2025<\/a> on deep sea mining, indicate how the US, within this sphere of influence, will \u201cmake\u201d the rules on the basis of its own interests and the power to support them<\/a>. This is evident also in relation to the operation in Venezuela, including the abduction of President Maduro, and with respect to Greenland<\/a>.<\/p>\n\n\n\n All this prompts the question of whether we find ourselves in a Grotian moment<\/a>, when even central rules supporting the architecture of interstate relations at sea may be subject to recalculation and recalibration, if not outright dismantling. This much was evidently clear also to Russia. While Lavrov<\/a> considered how this incident is putting \u201cinternational law to the test\u201d, he also recognized that \u201cthe provisions contained in the 1982 Convention on the Law of the Sea are [not] eternal\u201d, but that if so, \u201cwe need to sit down and agree on how to behave on the high seas and in special economic zones\u201d. This indicates that the Russian Federation may be open to the idea of re-writing some of the existing rules, so long as that is done cooperatively. Nevertheless, Russia highlighted that the arrest of the Bella1\/Marinera<\/em> was in breach of international law and will continue to protest<\/a> US actions if the operations against \u201cdark fleet\u201d tankers continue<\/a>.<\/p>\n\n\n\n All these shifts may carry serious repercussions for the law of the sea. First of all, the legitimacy of US FoNOPs will most likely come under increased scrutiny. At the time of writing there has been limited condemnation of the US practice of detaining tankers on the high seas based on its own national legislation and sanctions beyond Russia. Nevertheless, such actions undermine the credibility of the FoNOpS, highlighting the importance of adhering to the principle of \u201cpracticing what you preach\u201d. This approach not only signals to US allies to target the \u201cdark fleet\u201d (as seen in the UK<\/a>, France<\/a>, and Belgium<\/a>), but it may also incentivize other states to adopt similar measures, potentially to the detriment of the US itself. For instance, Iranian forces recently attempted to board<\/a> the US-flagged Stena Imperative<\/em> in the Strait of Hormuz \u2014 and following the US\/Israel illegal attack<\/a> on Iran they targeted it again<\/a>. While the Stena Imperative <\/em>case and the situation of the Strait of Hormuz<\/a> are different than the interception of the Bella 1\/Marinera<\/em> and the Operation Southern Spear on both points of law and facts, they might instances pointing to a changing sensibility \u2013 and state practice – with regards to freedom of navigation. <\/p>\n\n\n\n The consequences of this \u201clegal re-ordering\u201d would be tangible. Maritime transport could become more expensive and vulnerable\u2014either through blocked sea lanes or the need for costly security measures like naval escorts. The facilitation of maritime transport relies on safe and predictable navigation and if the US practice becomes more widespread, it is almost certain that it will affect the global shipping industry and not only the ships of the \u201cdark fleet\u201d.<\/p>\n\n\n\n These incidents thus underscore a further risk of the erosion of core principles such as the freedom of navigation which is one of the main pillars of the law of the sea. If the freedom of navigation is disregarded, the stability of the law of the sea, and international law in general, could be in question. The law of the sea has long provided safeguards for community interests against (excessive) sovereign claims of coastal states, especially in regional settings such as the Arctic or the South China Sea. But if the primary benefactor and supporter of global navigational freedoms ceases to uphold them, fundamental changes to the international legal framework may follow. <\/p>\n\n\n\n The arrest of the Bella 1\/Marinera<\/em> could in the future be considered a pivotal moment in the law of the sea. We have argued that the arrest itself is illegal under the law of the sea, but it can still signify a change of practice of the US having repercussions that may affect the international legal ordering of the oceans for years to come. The interception of the Bella 1\/Marinera<\/em> may incentivize \u201cillegal reciprocity\u201d, emboldening other States to adopt similar measures under the guise of reciprocity, and without feeling the need to adhere to rules that are not respected by their counterparts. Indeed, Lavrov\u2019s indication that Russia might be open to reconsider existing rules points precisely in the direction of a change in legal ordering. Such a situation far exceeds the narrow question of the legality of the interception. It opens up scenarios where a new legal order of the sea may be negotiated based on strategic considerations of a select number of big powers, leaving the rest of the world behind, particularly those States that do not want to align themselves with these powers in one way or another.<\/p>\n\n\n\n This post may be cited as<\/strong>: Konstantinos Deligiannis Virvos, Vito De Lucia and Jan Jakub Solski, \u2018Interceptions in the high seas: from a question of legality to a question of legal (re-)ordering\u2019, The<\/em> NCLOS Blog<\/em>, 10 March 2026.<\/p>\n\n\n\n To subscribe to The NCLOS Blog<\/em> by email, please go to http:\/\/site.uit.no\/nclos\/<\/a>.<\/p>\n2. The Legality of the Interception of the Bella 1\/Marinera<\/em><\/h1>\n\n\n\n
3. A Legal (re-)ordering?<\/h1>\n\n\n\n
4. Concluding Remarks<\/h1>\n\n\n\n