The West found a miles-long piece of evidence backing its claim Russia is purposely cutting undersea cables

• Finland accused a Russian ship of dragging its anchor to sever undersea cables in the Baltic.
• It says the vessel, Eagle S, is part of a "shadow fleet" that transports sanctioned oil.
• Russia is escalating its threats to the undersea cables that power communications.

Western nations have long suspected that Russia is seeking to deliberately sever vital underseas cables — but without much to prove it.

That may have changed after officials pointed to an unusually vivid piece of evidence tied to a Russia-linked ship.

Finnish officials on Sunday said they found miles and miles of tracks on the bed of the Baltis Sea pointing to a Russia-linked tanker in the slicing of a cluster of valuable data and power cables.

Sami Paila, tactical leader and detective chief inspector of Finland's National Bureau of Investigation, said in a statement quoted by Reuters that "dragging marks" from an aging tanker's anchor had been found beneath the Baltic Sea near the cables.

"The track is dozens of kilometres in length," Paila said.

Germany's foreign minister on Friday cited the incident as a "wake-up call," saying it would be naive to consider it an accident.

The minister, Annalena Baerbock, pushed for further European sanctions on the so-called "shadow fleet" of ships tied to Russia.

Finnish officials boarded the Eagle S after the Estlink 2 subsea cable carrying electricity and four other cables carrying data were damaged on December 25.

Estlink 2 is one of two carrying electricity between Finland and Estonia. Officials have said it might not be functional again until August, Reuters reported.

Finnish telecommunications firm Cinia said the severance of one of the data cables caused disruptions in internet communications between Rostock, Germany, and Helsinki, Finland, and could take weeks to repair.

The cable damage is the latest in a series of similar incidents.

Eagle S was carrying around 35,000 tons of unleaded gasoline loaded in Russian ports. It was registered in the Cook Islands, and was travelling to Egypt when stopped by the Finnish coast guard.

Finnish officials say it's likely part the "shadow fleet," a network of vessels registered through complex ownership schemes that seek to undermine international sanctions on Russia's oil trade.

It's the first time a part of the fleet has been accused of involvement in subsea cable sabotage.

"The suspected vessel is part of Russia's shadow fleet, which threatens security and the environment, while funding Russia's war budget," said Kaja Kallas, the chief foreign-affairs official for the EU.

"We will propose further measures, including sanctions, to target this fleet," said Kallas' statement on X.

Russia has long denied that it is seeking to damage subsea cables in the Baltic. Business Insider has contacted the Russian embassy in the UK for further comment.

Internet cables between Germany and Finland and Sweden and Estonia were damaged in November, with a Chinese vessel detected in the vicinity when the damage occurred.

Estonia on Friday said it would be stepping up efforts to defend the undamaged Estlink 1 cable.

"We've decided to send our navy close to Estlink 1 to defend and secure our energy connection with Finland," Estonian Defense Minister Hanno Pevkur said.