In less than 14 months, submarine telecommunications cables connecting Estonia, Finland, Germany, Lithuania, Russia, and Sweden have been cut nine times in the Baltic Sea. In addition, an underwater electricity cable and a gas pipeline have been cut by a ship anchor. These damages occurred in three separate incidents all involving a foreign commercial ship dragging an anchor on the seafloor for over a hundred kilometres.
The NewNew Polar Bear incident occurred in October 2023, the Yi Peng 3 incident occurred in November 2024, and the Eagle S incident took place on 25 December 2024. As indicated on the map below, almost all objects of the Estonian critical offshore infrastructure located outside the limits of the territorial sea were damaged in the NewNew Polar Bear and Eagle S incidents. The ESTLINK 1 electricity cable and three data cables were unharmed, owing to Finland’s decisive intervention in the Eagle S incident.
Map 1. Damage to the critical offshore infrastructure in the Gulf of Finland in the NewNew Polar Bear and the Eagle S incidents. This map serves an illustrative purpose only.
Source: Based on the Submarine Cable Map and Marine Traffic data.
The Eagle S Incident
In December 2024, the submarine electricity cable ESTLINK 2 connecting Estonia and Finland and four data cables were cut in the Finnish exclusive economic zone (EEZ). Of these, three submarine telecommunications cables (FEC-1, FEC-2, CITIC Telecom) connect Estonia and Finland, while the C-Lion1 (which was also cut in the Yi Peng 3 incident of November 2024, see here for my earlier post on the incident) is the only telecommunications cable linking Finland and Germany. The ESTLINK 2 cable was cut in the Finnish EEZ, and the repair works might last until summer 2025. Due to a fault and costly repairs, ESTLINK 2 was out of operation for nine months earlier in 2024, raising electricity costs in Estonia by about a tenth.
As the Eagle S continued the anchor-dragging and sailed westward, the Finnish Defence Forces and Coast Guard intervened off Helsinki and Tallinn (see Map 1). They used a patrol ship and two helicopters to stop and board the Cook Islands-flagged Eagle S, forming part of the Russian sanctions-busting ‘shadow fleet’. The ship was stopped just before it would have crossed the ESTLINK 1 electricity cable, the Balticconnector gas pipeline, and other underwater cables.
The chronology of the events is described here and here. In brief, the Finnish patrol ship Turva started to shadow the Eagle S off Helsinki and noticed that its anchor was dropped. Turva requested the Eagle S to raise its anchor and enter the Finnish territorial sea. The Eagle S complied with the order. As the many tons heavy anchor chain of the Eagle S was heaved up, it became clear that the ship had lost its main anchor.
The special forces (Karhu) of the Finnish Defence Forces and the Coast Guard boarded the ship from two helicopters and took command of the Eagle S after the ship had entered the Finnish territorial sea (see Map 2). The Finnish President Mr. Alexander Stubb confirmed that the ship was boarded in the Finnish territorial sea.
Map 2. The Estonian and Finnish Maritime Zones in the Gulf of Finland
Source: This map was originally published here.
It is unclear whether Finland consulted with the flag State prior to interdicting the ship. In any event, the flag State consent to board and seize the ship was not required as the Finnish laws were enforced only after the ship had agreed to enter the Finnish territorial sea. Yet, notably, according to the Finnish press report, the Finnish authorities were ready to take measures against the ship even if it had not agreed to enter the Finnish territorial sea. In this time-critical situation, this would have been necessary to avoid damages to the ESTLINK 1 electricity cable, the Balticconnector gas pipeline, and to the other submarine data cables (see Map 1).
The Finnish investigation is underway into the damages caused to the offshore infrastructure as aggravated criminal mischief. A 3-kilometer no-fly zone was established around the ship, the Eagle S that is loaded with 35,000 tons of unleaded Russian petrol was arrested and taken to the Svartbäck inner anchorage area, while a 1-mile-wide no-enter zone was established around the ship. The Finnish criminal jurisdiction can be exercised on the grounds of the damage caused to the submarine cables and, possibly, for violating the European Union (EU) sanctions. The EU has prohibited the shipments of Russia’s oil to non-EU countries, unless these products are being sold in accordance with the oil price cap. The violation of the sanctions is a crime at the EU level.
Hi-tech transmitting and receiving devices used for intelligence purposes were found on-board the ship (see here and here). In my view, if the evidence shows that a foreign State orchestrated and instructed the attack against the critical offshore infrastructure with the aim of cutting the majority, if not all of the coastal State’s data cables, its electricity cables, and the submarine gas pipeline, thereby causing damages of hundreds of millions of euros and potential disruptions in the public services (internet, electricity, etc), then it could potentially be classified as a use of force reaching the level of an armed attack under Article 51 of the United Nations Charter.
It is rather unlikely that the Eagle S incident would be challenged before an international court or tribunal as the flag State has distanced itself from the ship and Finland exercised its criminal jurisdiction in its territorial sea (Art 23 of the UNCLOS) and not within the EEZ corridor in the Gulf of Finland where the coastal State’s right of interdiction in response to such incidents is unclear and untested.
The Eagle S Incident as a Precedent
The interdiction of the Eagle S by the Finnish Defence Forces and the Coast Guard sets a precedent that can be followed by other States in the future. It is significant for many reasons. Most importantly, it is the first time that the Baltic Sea coastal State has taken resolute steps against a commercial ship caught ‘red-handed’ for a suspected intentional damaging of the coastal State’s critical offshore infrastructure.
In October 2023, the Hong Kong-flagged container ship NewNew Polar Bear damaged in the Finnish and Estonian EEZ the Balticconnector pipeline that runs between Finland and Estonia and three submarine telecommunications cables. The flag State (China) has confirmed that the NewNew Polar Bear damaged the pipeline and the submarine cables with her anchor. Yet it has been challenging to gather the necessary evidence to decide whether it was an accident or an intentional act, since the flag State has not cooperated with the investigation. Henrik Ringbom and I have discussed the implications of this incident to the law of the sea here.
In November 2024, a submarine telecommunications cable linking Lithuania and Sweden and the C-Lion1 submarine telecommunications cable linking Finland and Germany were cut in Sweden’s EEZ. I analysed the legal avenues for boarding and inspecting the suspected ship Yi Peng 3 and advised that, irrespective of whether the ship cooperates with the authorities and whether the coastal State authorities receive the flag State’s consent to inspect the Yi Peng 3 in the Danish EEZ, the coastal authorities may rely on additional legal bases for interdicting the Yi Peng 3. It appears that, aside stopping the ship, these avenues were essentially not used in the Yi Peng 3 case, leading China to deny Sweden’s request for prosecutors to board the ship. Yi Peng 3 departed from the Danish EEZ less than a week before the Eagle S incident.
In reaction to the Eagle S incident, the Estonian Prime Minister Mr. Kristen Michal signalled that Finland’s ‘completely novel response’ to the protection of critical offshore infrastructure outside the limits of the territorial sea is a welcome development. It was preceded with the Finnish Defence Minister Mr. Häkkänen’s statement in the aftermath of the Yi Peng 3 incident, according to which it is quite clear that if critical infrastructure has been destroyed or seriously damaged, and it is necessary to find out who did it, then it cannot be a situation where the victim State does not intervene.
However, even after the Christmas Day cable cuts, the question remains about whether the coastal State can board and seize a commercial ship in the EEZ if it damages the coastal State’s critical offshore infrastructure? Unfortunately, the current legal framework does not provide a clear answer to this question. Nonetheless, in my view, the answer is positive. But there are important caveats. Most importantly, the right of interdiction is more complex in relation to cable cuts, since they do not cause environmental pollution (unlike a pipeline rupture). Therefore, presumably, the coastal State cannot base its enforcement jurisdiction on Articles 79(2) and 221 of the UNCLOS.
Calls for Providing a Stronger Legal Regime for the Protection of Offshore Infrastructure
The Eagle S incident has led Estonia to consider avenues for increasing the legal certainty in respect of the protection of critical infrastructure outside the limits of the territorial sea. The Estonian Government convened a day after the Eagle S incident for an emergency meeting. At the press conference, the Estonian Prime Minister, the Minister of the Interior, and the Minister of Justice and Digital Affairs stressed the importance of changing the legal framework so that it would be better suited for addressing the security gap in respect of the protection of critical offshore infrastructure. The Estonian Prime Minister promised to raise this issue at the European Union and NATO levels.
The Minister of Justice and Digital Affairs announced that the Estonian Government will apply to the International Maritime Organization by February 2025 to update the legal framework in relation to the protection of critical offshore infrastructure. At this stage, it is unclear what the potential proposals for closing the security gap in the legal framework applicable to submarine cables and pipelines might entail. To open the discussion, I am raising a couple of ideas, while acknowledging that any effective measures for closing the current security gap would likely negatively impact the freedom of navigation. I am afraid that this is the price States would have to pay for safeguarding the underwater choke points of the internet and energy transportation outside the limits of the territorial sea.
As suggested by Wolff Heintschel von Heinegg (at p. 311), one possibility is to consider granting universal enforcement jurisdiction in respect of ships suspected of damaging submarine pipelines and cables outside the limits of the territorial sea. Such universal jurisdiction has been granted over piracy and unauthorized broadcasting on the high seas and in the EEZ under Articles 58(2) and 110(1) of the UNCLOS. Given the importance of submarine pipelines and submarine cables that carry over 95% of global internet traffic and thus serve as the backbone of the global internet-based world economy, a similar legal approach to that of tackling piracy and unauthorized broadcasting would, in my view, be reasonable for the protection of critical offshore infrastructure located outside the limits of the territorial sea. The Estonian Minister of Justice and Digital Affairs Ms. Liisa Pakosta hinted at this in a recent interview for the Reuters.
According to the dominant view among States, Article 113 of the UNCLOS, which regulates the breaking or injury of a submarine cable or pipeline, does not provide for universal jurisdiction. Criminal jurisdiction can be implemented by the relevant coastal State, and only if the cable is damaged by a national of the coastal State or a ship flying its flag. States could reduce these limitations by building on Article 10 of the 1884 Paris Convention for the Protection of Submarine Cables Outside the Territorial Sea. But the problem with Article 10, which is considered by the United States to form part of customary international law (at p. 16), is that it enables to board a ship outside the territorial sea and only question the crew. Would there be room for granting universal enforcement jurisdiction for inspecting and, if necessary, detaining the suspected ship and its crew for damaging critical offshore infrastructure outside the limits of the territorial sea?
Alternatively, States could consider reaching a broader understanding on whether the international law of the sea enables to establish safety zones around submarine cables and pipelines in the EEZ. In the EEZ, it is permitted to establish safety zones around and above such subsea facilities as artificial islands, installations and structures, whereas submarine cables and pipelines are excluded from the scope of Article 60(4) of the UNCLOS. The 2024 report of the ILA Committee on Submarine Cables and Pipelines found that safety zones are not permitted around cables and pipelines as they do not qualify under the definition of installations and structures, though the Committee might be open to the idea that there might be legal developments which support the establishment of safety zones around cables in the EEZ in the future (at pp. 22-23).
The Danish Cable Order in combination with the Offshore Safety Act, New Zealand’s Submarine Cables and Pipelines Protection Act (Section 12), and the Australian Telecommunications Legislation (Sections 3a, 36-38, 44A) seem to signal that it is possible to establish safety zones around submarine cables and pipelines also in the EEZ. Even though this practice might be considered as ‘creeping jurisdiction’, it could provide – in combination with other legal concepts, including the right of hot pursuit – an effective measure for closing the current security gap embedded in the UNCLOS especially for those coastal States that are dependent on the protection of their underwater infrastructure.
Safety zones have not been established in the EEZ corridor of the Gulf of Finland where damages to numerous data and power cables as well as to the submarine gas pipeline occurred in October 2023 and December 2024. However, the Finnish response to the damaging of the five submarine cables in December 2024 showcased to some extent how the interdiction based on the safety zones (Art 60(4-7) of the UNCLOS) and hot pursuit (Art 111 of the UNCLOS) could potentially be effectuated in practice, if allowed to be applied in respect of cables and pipelines in the EEZ.
Notably, safety zones cannot be established on the high seas. Their use would be limited to the territorial sea and EEZ where cables and pipelines are mostly damaged by ship anchors (possibly, because the sea tends to be not as deep as on the high seas). Thus, it would promise a new protection mechanism for cables and pipelines located in most regional and semi-enclosed seas, such as the Black Sea, the Mediterranean, the North Sea, and the Baltic Sea, and other maritime areas that are entirely subject to the coastal States’ jurisdiction. The safety zones permit the coastal State to broaden the reach of her enforcement jurisdiction in the relevant parts of the EEZ in respect of ships suspected of damaging critical offshore infrastructure, whereas not otherwise impeding the free navigation of ships that are not suspected of damaging critical offshore infrastructure.
Conclusion
The Christmas Day incident in the Gulf of Finland marks the first successful response of the Baltic Sea coastal State to a suspected intentional damaging of critical offshore infrastructure located outside the limits of the territorial sea. Recognising the coastal State’s right to interdict a ship that is caught ‘red-handed’ in the EEZ for the damages caused to underwater infrastructure and for preventing further destruction of cables and pipelines on the seafloor is necessary to respond to the challenges posed by hybrid warfare at sea.
