Finnish investigators probing the damage to a Baltic Sea power cable and several data cables said they found an anchor drag mark on the seabed, apparently from a Russia-linked vessel that has already been seized.

The Christmas Day cutting of four Internet cables and one power cable will cause NATO to boost its presence in the Baltic Sea. Finland last week seized the Eagle S ship, carrying Russian oil, under suspicion of being behind the cuts. “NATO will enhance its military presence in the Baltic Sea,” NATO secretary general Mark Rutte said.

Finnish investigators have linked damage to the Estlink-2 power cable in the Baltic Sea to a Russian-linked vessel, the Eagle S. Anchor drag marks stretching nearly 100 kilometers were discovered, and an investigation is underway to determine intent,

NATO said on Friday it would boost its presence in the Baltic Sea after the suspected sabotage this week of an undersea power cable and four internet lines, while alliance member Estonia launched a naval operation to guard a parallel electricity link.

Finnish authorities discovered anchor drag marks on the seabed just a day after it moved the Eagle S to a safer anchorage to help further its investigation.

Finnish investigators have uncovered an underwater trail stretching nearly 100 kilometers around the site where a cable was severed on Christmas Day. The ship suspected of carrying out this act of sabotage is named Eagle S and sails under the flag of the Cook Islands.

Finnish police said on Sunday they had found tracks that drag on for dozens of kilometres along the bottom of the Baltic Sea where a tanker carrying Russian oil is suspected of breaking a power line and four telecoms cables with its anchor.