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.

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.

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.

General Mark Rutte says the military alliance will step up patrols in the Baltic Sea area as Finnish investigators work to establish whether a ship linked to Russia sabotaged undersea cables there this week.

Baltic Sea countries have been on high alert after a string of outages of power cables, telecom links and gas pipelines since Russia invaded Ukraine in 2022

Police and media reports say that Finnish authorities have detained a Russia-linked ship as they investigate whether it damaged a Baltic Sea power cable and several data cables.

Finnish police have discovered traces on the bottom of the Baltic Sea stretching for dozens of kilometers. It is believed that a tanker, which was carrying Russian oil, severed a power line and four telecommunications cables with its anchor,