The Finnish operator of the cables suspected to have been damaged by a vessel from Russia's shadow fleet on Christmas Day says the cables have now been repaired. A power cable damaged that day is still out of service.

Two undersea telecom cables linking Estonia and Finland have been repaired following suspected sabotage, Finnish operator Elisa announced Monday.

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.

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.

Two undersea telecommunications cables that were damaged in the Baltic Sea on Dec. 25 appeared to have been torn apart by a strong external force, Finland's Elisa said on Monday, adding that they had now been repaired.