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 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.

Finnish authorities seized the Russian oil tanker Eagle S after the country’s police opened a criminal investigation into the vessel’s possible involvement in another cutting of undersea power and communications cables in the Baltic Sea on Christmas Day,