By Essi Lehto and Andrius Sytas
HELSINKI (Reuters) -Finnish authorities on Thursday seized a ship carrying Russian oil in the Baltic Sea on suspicion it caused the outage of an undersea power cable connecting Finland and Estonia a day earlier, and that it also damaged or broke four internet lines.
The Cook Islands-registered ship, named by authorities as the Eagle S, was boarded by a Finnish coast guard crew that took command and sailed the vessel to Finnish waters, a coast guard official said at a press conference.
"From our side we are investigating grave sabotage," said Robin Lardot, director of the Finnish National Bureau of Investigation.
"According to our understanding, an anchor of the vessel that is under investigation has caused the damage," he added.
The Finnish customs service said it had seized the vessel's cargo and that the Eagle S was believed to belong to Russia's so-called shadow fleet of ageing tankers that seek to evade sanctions on the sale of Russian oil.
Two fibre-optic cables owned by Finnish operator Elisa linking Finland and Estonia were broken, while a third link between the two countries owned by China's Citic was damaged, Finnish transport and communications agency Traficom said.
A fourth internet cable running between Finland and Germany and belonging to Finnish group Cinia was also believed to have been severed, the agency said.
"We are coordinating closely with our allies and stand ready to support their investigations," said a spokesperson for the U.S. National Security Council, adding that the incident underscored the need for closer international cooperation on safeguarding critical undersea infrastructure.
"We are following investigations by Estonia and Finland, and we stand ready to provide further support," NATO Secretary General Mark Rutte said in a post on social media X.
Both the Finnish and Estonian governments held extraordinary meetings on Thursday to assess the situation, they said in separate statements.
Baltic Sea nations are on high alert for potential acts of sabotage following a string of outages of power cables, telecom links and gas pipelines since 2022, although subsea equipment is also subject to technical malfunction and accidents.
The European Union said it strongly condemned any deliberate destruction of the continent's infrastructure.
"We commend the Finnish authorities for their swift action in boarding the suspected vessel," said a joint statement from EU foreign policy chief Kaja Kallas and the European Commission, the bloc's executive body.
Repairing the 170-km (106-mile) Estlink 2 interconnector will take months, and the outage raised the risk of a strained power supply during the winter, operator Fingrid said in a statement.
Estonian Prime Minister Kristen Michal said, however, that his country would continue to have sufficient access to electricity.
The Eagle S Panamax oil tanker crossed the Estlink 2 electricity cable at 1026 GMT on Wednesday, a Reuters review of MarineTraffic ship tracking data showed, identical to the time when Fingrid said the power outage occurred.
United Arab Emirates-based Caravella LLCFZ, which according to MarineTraffic data owns the Eagle S, did not immediately respond to a request for comment.
Peninsular Maritime, which, according to MarineTraffic acts as a technical manager for the ship, declined to comment outside of the company's opening hours.
'DISRUPT AND DETER'
Damage to subsea installations in the Baltic Sea has now become so frequent that it is difficult to believe this was caused merely by accident or poor seamanship, Estonian Foreign Minister Margus Tsahkna said in a statement.
"We must understand that damage to submarine infrastructure has become more systematic and thus must be regarded as attacks against our vital structures," Tsahkna said.
The 658 megawatt (MW) Estlink 2 outage began at midday local time on Wednesday, leaving only the 358 MW Estlink 1 in operation between the two countries, operator Fingrid said.
Twelve Western countries on Dec. 16 said they had agreed on measures to "disrupt and deter" Russia's so-called shadow fleet of vessels in order to prevent sanctions breaches and increase the cost to Moscow of the war in Ukraine.
"We must be able to prevent the risks posed by ships belonging to the Russian shadow fleet," Finnish President Alexander Stubb said in a post on social media X on Thursday.
Lithuanian foreign minister Kestutis Budrys said the growing number of Baltic Sea incidents should serve as a stark and urgent warning to NATO and the European Union to significantly enhance the protection of undersea infrastructure there.
Police in Sweden are leading an investigation into the breach last month of two Baltic Sea telecom cables, an incident German Defence Minister Boris Pistorius said he assumed was caused by sabotage.
Separately, Finnish and Estonian police continue to investigate damage caused last year to the Balticconnector gas pipeline linking Finland and Estonia, as well as several telecom cables, and have said this was likely caused by a ship dragging its anchor.
In 2022 the Russia-to-Germany Nord Stream gas pipelines running along the seabed in the same waters were blown up, in a case still under investigation by Germany.