Finland's public transport agency said on Wednesday that an oil tanker suspected of damaging undersea cables in the Baltic Sea has been found to have serious deficiencies and will not be allowed to operate until repairs have been made.

Finnish police said on Thursday they are investigating whether a foreign ship was involved in the damage of an undersea power cable connecting Finland and Estonia following a sudden outage on Wednesday.

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.