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.

Finland’s prime minister says authorities are investigating an interruption in a power cable under the Baltic Sea between his country and Estonia.

A tanker from the "Russian shadow fleet," sailing under the Cook Islands flag, is suspected of damaging the EstLink 2 underwater power cable. Estonian telecommunications operators reported on Thursday that data transmission on four submarine cables was disrupted.