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 has seized an oil tanker suspected of having severed undersea power and internet cables, with Finnish authorities saying the vessel may have been part of Russia's "shadow fleet" of ships aimed at skirting Western sanctions.

Finnish authorities are investigating an oil tanker that is part of Russia’s shadow fleet over whether it cut an electricity cable between Finland and Estonia. The Eagle S was stopped by Finnish authorities after the Estlink 2 subsea electricity cable in the Gulf of Finland was disconnected on Wednesday.