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 member Estonia has deployed a naval warship to defend its underwater power cables after a Russian vessel allegedly cut one of the wires in yet another act of sabotage against the allied nations.

NATO Secretary-General Mark Rutte said Friday that the military alliance will step up patrols in the Baltic Sea region as Finnish investigators work to establish whether a ship linked to Russia sabotaged undersea cables there this week.

A Russia-linked tanker suspected of cutting Baltic Sea cables has been tugged to port amid reports it was loaded with “spy equipment”.

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.

A power cable connecting Finland and Estonia under the Baltic Sea suffered a power outage on Wednesday, prompting an investigation.

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.

NATO allies met on Dec. 30 to address the security of critical infrastructure in the Baltic Sea, following damage to undersea cables connecting Estonia and Finland several days earlier.