‘FL7726SH’: Between The Law of the Sea and the Jus ad Bellum?

In the morning of Wednesday 25 February 2026, a Cuban government vessel carrying five border guard troops approached a speedboat, registered in the U.S. as FL7726SH, after it had, according to Cuba’s Interior Ministry, entered its territorial waters in Falcones Cay, Villa Clara province. Upon being approached for identification by the Cuban vessel, the crew of the speedboat allegedly opened fire leading to the wounding of one Cuban commander and, in the ensuing exchange of fire, four of the people on board the speedboat were killed, with the other six wounded.

Cuba claimed that the group was comprised of U.S. based anti-government Cubans, some of whom were previously wanted for plotting other attacks, and that the individuals on this occasion were allegedly trying to infiltrate the island ‘for terrorist purposes’. Shortly after the incident U.S. Secretary of State Marco Rubio stated that the U.S. had not been involved and that it would carry out its own investigation, and Cuba has not expressly alleged direct U.S. involvement. 

Using the FL7726SH incident as a vehicle for analysis, this short piece places the incident in the context of the relevant law of the sea whilst, at the same time, identifying some of the intersections between this framework and the jus ad bellum in general but also as they emerged during the incident, and the possible implications of this. 

A tale of two prohibitions

The United Nations Convention on the Law of the Sea (UNCLOS) provides that ‘ships of all States, whether coastal or land-locked, enjoy the right of innocent passage through the territorial sea’ (Article 17, UNCLOS). In that respect, vessels are prohibited from engaging in non-innocent passage. While defining such passage as an activity which is ‘prejudicial to the peace, good order or security of the coastal State’ (Article 19(1), UNCLOS), included more specifically within this is the prohibition of the ‘threat or use of force against the sovereignty, territorial integrity or political independence of the coastal State, or in any other manner in violation of the principles of international law embodied in the Charter of the United Nations’ (Article 19(2)(a), UNCLOS).  

A notable aspect of the prohibition found within Article 19(2)(a) of UNCLOS is that it is a near exact replication of the prohibition of force found within Article 2(4) of the UN Charter (1945). While the application of the prohibition in Article 2(4) is restricted to the acts of states or non-state entities acting under the control or direction of a state, meaning that it was not applicable to the incident involving FL7726SH, the prohibition as found within Article 19(2)(a) applies to the acts of all ships whether warships, merchant ships or private foreign vessels with no requirement for direct state involvement in the activities concerned, meaning that it is a prohibition that FL7726SH was seemingly in breach of. More generally, however, such a replication in wording between the two prohibitions might appear a little odd as it would seem to be applying, in essence, what many perceive (or, at least, used to perceive) to be a fundamental jus cogens norm in Article 2(4) to the activities of non-state actors in Article 19(2)(a), albeit without the formal associated elevated consequences of a breach. 

A blurring between ‘rights of protection’?

It is, however, in regards to the rights that states have to protect themselves in this context that the relationship between the law of the sea and the jus ad bellum becomes most interesting, something which the FL7726SH incident particularly highlights. Indeed, in addition to having certain ‘rights of protection’ including to ‘take the necessary steps in its territorial sea to prevent passage which is not innocent’ (Article 25(1), UNCLOS), a coastal state also has the additional right of protection in the form of the right of self-defence within Article 51 of the UN Charter and customary international law. 

It was in this light significant that within Cuba’s initial categorisation of its actions on this occasion it talked of protecting its territorial waters not expressly under the right of protection contained within UNCLOS, but rather ‘based on the principle that national defense is a fundamental pillar of the Cuban State in safeguarding its sovereignty and ensuring stability in the region’ (emphasis added). Cuban President Miguel Diaz-Canel also stated that ‘Cuba will defend itself with determination and firmness against any terrorist and mercenary aggression that seeks to affect its sovereignty and national stability’ (emphasis added). While not specifically talking in terms of the activities of FL7726SH constituting an ‘armed attack’ for the purposes of Article 51 of the UN Charter (states rarely do), their depiction as an ‘aggression’ against the Cuban state appeared to sound rather as if it were talking in terms of acting upon the right of self-defence.

There are some distinct similarities between these two rights of protection, the right to prevent passage which is not innocent, and the right to self-defence. First, both apply to acts against a state within its territorial seas, meaning that both were potentially applicable in this incident. Secondly, both rights apply to the acts of both state and non-state actors. In the context of the Article 25 ‘necessary steps’, the taking of these is based on the enforcement jurisdiction of the coastal state within its territorial seas. State actors normally have immunity from the enforcement jurisdiction of other states, yet Article 32 of UNCLOS provides that immunities in this context are subject to the ‘exceptions as are contained in subsection A and in articles 30 and 31’ of UNCLOS. Both the prohibition of non-innocent passage and the rights of protection of the coastal state in response to such passage are indeed located within subsection A which includes the ‘rules applicable to all ships’ (emphasis added). Similarly, although not a view completely free from controversy, it is arguably the majority view today that both state and non-state actors (acting independently of state involvement) are able to perpetrate armed attacks for the purposes of the right of self-defence (see e.g. here at p. 264).

However, there are also some notable distinctions between the two rights which potentially make the Cuban statements above relevant. On the one hand, the rights of protection provided under UNCLOS are broader than those provided in the form of the right of self-defence, in that coastal steps are permitted to take undefined ‘necessary steps’ in response to a range of non-innocent activities (see Article 19(2)(a)-(l), UNCLOS) (although the resort to any forcible measures would need to be a last resort and not go beyond what is reasonable and necessary in the circumstances (see M/V Saiga (no. 2), at para. 155)), whereas self-defence is limited to necessary and proportionate responses specifically to ‘armed attacks’. In this respect, while the activities of FL7726SH as set out above arguably constituted non-innocent passage justifying the taking of forcible necessary steps, the scale and effects of the exchange of fire might seem to place the incident within the realms of constituting a so-called ‘mere frontier incident’ rather than a full-fledged ‘armed attack’ for the purposes of the right of self-defence (as described by the ICJ in the Nicaragua case, at para. 195, despite some disagreement with the Court on the existence of such a distinction, see e.g. here at pp. 277-286 and here at p. 210).

On the other hand, however, the rights of protection provided within UNCLOS are clearly narrower and more restrictive than those provided in the form of the right of self-defence. For example, as the necessary steps permitted in Article 25 are based upon the law enforcement jurisdiction of the state within its territorial seas they are therefore restricted to the taking of any steps within this maritime zone. Whether or not Cuba had claimed U.S. involvement, it would not have been able to extend any necessary steps to the territory of the U.S. The right of self-defence, on the other hand, exists for the very purpose of exceptionally excusing or justifying a forcible violation of state sovereignty, including that of a state’s territorial integrity.

It was in this respect that a notable aspect of Cuba’s justification was that its rights of protection were invoked ‘[i]n the face of current challenges’, something which might be seen as alluding to the current broader tensions between it and the U.S. More specifically, the Deputy Minister of Foreign Affairs of Cuba contextualized this event within the historical dispute between the two states, stating that ‘[t]his is not an isolated act’ and recalling that Cuba ‘has been the victim of aggressions and countless terrorist acts for more than 60 years’ emanating from U.S. territory. In recent years, he said, the Cuban authorities have denounced the increase in these violent plans and the ‘feeling of impunity that prevails in the organizers and executors in the face of the inaction’ of the authorities of that country, clearly laying blame on the U.S. for allowing such groups to operate freely.

Consequently, while Cuba was arguably acting under the right of protection within Article 25 during the 25 February incident, it is not beyond the realms of possibility that these claims could be used to lay the ground for either direct attribution of the accumulated ‘aggressions’ to the U.S. or, in the alternative, for Cuba to make some kind of ‘unable or unwilling’ self-defence argument against the U.S. with the FL7726SH incident forming the most recent part of it. 

Conclusion

This incident involving FL7726SH reminds us, as if one were needed, of the need for clarity in the articulation by states of the actions of others and their responses to them. Yet, it also more broadly highlights the lack of clarity regarding the relationship and distinction between the law of the sea and jus ad bellum frameworks and the conduct that falls, or potentially could fall, under them. As discussed in this post, this issue becomes important given the breadth and scope of permissible responses that each potentially entail. While scholars have previously noted this issue and, in response, called for greater clarity (see e.g. here), the increasingly tense geopolitical situation in different geographical areas and maritime zones means that fully understanding the distinction and relationship between these frameworks is more necessary now than ever.