The Estonian Navy protects an underwater power cable after the main link is damaged

NATO said it would increase its military presence in the Baltic Sea and Estonia sent a patrol ship to protect its Estlink1 undersea power cable after Russia was accused of sabotaging its main power line in the Gulf of Finland.

The ship, named Eagle S, is suspected to have damaged the Estlink 2 cable, and the Finnish Coast Guard crew boarded the oil tanker and steered it into Finnish waters.

The EU said the Eagle S was part of Russia’s “shadow fleet” and that the submarine cable had failed “the latest in a series of alleged attacks on critical infrastructure”.

Estonian Defense Minister Hanno Peukur said the Raju had left on Friday morning and he believed Finland would join the operation to protect the remaining cable.

He told Estonian public radio that Raju’s task was to “make sure that nothing happens there and that our important link with Finland remains operational.”

NATO Secretary General Mark Rutte announced on social networks that he spoke with the President of Finland, Alexander Stubb, adding that NATO will increase its presence in the Baltic.

Finland and Estonia are NATO members, and Estonian Prime Minister Kristen Michal told public television that if necessary, they would invoke Article 4 of the NATO Treaty, which provides for consultations if any member country feels threatened.

“Our desire would be to receive reinforcements from NATO in the form of a fleet that would act as a deterrent,” the BNS news agency quoted him as saying.

Estonia’s power supply has been cut sharply after the 170-kilometer (105-mile) Estlink 2 cable was shut down.

In its initial assessment on Thursday, Finnish company Fingrid said the cable repairs could last until the end of July 2025.

The damage to Estlink 2 was the third incident in just over a month in the Baltic Sea.

Two data cables were cut last month: the Arelion cable between the Swedish island of Gotland and Lithuania on November 17, followed by damage to the C-Lion 1 cable between the Finnish capital Helsinki and the German port of Rostock.

A Chinese ship, the Yi Peng 3, was suspected of dragging an anchor through cables in a separate act of Russian sabotage.

In October 2023, another Chinese ship ruptured an underwater gas pipeline between Finland and Estonia.

The Yi Peng 3 and Eagle S are suspected to be part of the so-called shadow fleet of oil tankers used by Russia to avoid Western sanctions imposed after the full-scale invasion of Ukraine.

The EU said it was working on measures, including sanctions, aimed at “Russia’s shadow fleet that threatens security and the environment”.

After weeks at anchor in the Kattegat Strait between Sweden and Denmark, the Chinese tanker was eventually taken on board by the authorities of Sweden, Denmark, Germany and Finland, but then set sail last week.

Instead, Finnish authorities said they boarded the Cook Islands-registered Eagle S in the early hours of Thursday and escorted it to the Finnish coast near Porkala, across the Gulf of Finland from Tallinn.

“Our patrol ship went to the area and was able to visually determine that the vessel’s anchor was missing,” said Marku Hasinen, deputy head of the Finnish border guard, at a press conference.

Estonia’s prime minister on Thursday sought to reassure Estonians that they will continue to have secure electricity supplies.

The two main energy companies, Elering and Eesti Energia, had different backup and standby power plants, he told reporters.

However, he added that it is impossible to protect every square meter of the seabed all the time.