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 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.

HELSINKI – An undersea power cable linking Finland and Estonia broke down on Dec 25, Finland’s Prime Minister said, the latest in a series of incidents involving telecommunications cables and energy pipelines in the Baltic Sea.

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.