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

Permanent representatives of NATO member countries met in Brussels today and agreed on measures to enhance the Alliance's presence in the Baltic Sea and protect critical undersea infrastructure following an incident involving damaged undersea cables.

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.