Nations on the Baltic Sea, along with NATO, have stepped up security after a third incident of suspected sabotage to underwater infrastructure in a month.

Finnish police have reported finding the anchor responsible for severing an undersea internet cable connecting Finland to Estonia. Last month, Finland detained the Eagle S, an oil tanker transporting Russian oil,

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 will strengthen its presence in the Baltic Sea following the outage of the Estlink 2 submarine power cable, Secretary General Mark Rutte said on Friday after speaking to Finnish President Alexander Stubb.

Finnish police said on Tuesday they have recovered a lost anchor from the bottom of the ocean as part of an investigation of suspected sabotage against power and internet cables in the Baltic Sea. Finland last month seized the Eagle S tanker carrying Russian oil on suspicion that the vessel had damaged the Finnish-Estonian Estlink 2 power line and four telecoms cables by dragging its anchor across the seabed.

The anchor of the Eagle S oil tanker has been recovered from the bed of the Baltic Sea during an inquiry into the ship's possible involvement in sabotage of maritime energy and communication cables. The EU says the tanker belongs to the so-called Russian shadow fleet.