The country’s prime minister said the incident, the latest in a series of disruptions to undersea infrastructure, underscored the danger of a so-called Russian shadow fleet.

An undersea power cable that runs between Finland and Estonia was disconnected on Christmas Day. Finland is pretty sure that Russia is to blame. On Thursday, Finnish authorities boarded an oil tanker that is part of Russia’s “shadow fleet” used to dodge sanctions and that just so happened to be spotted passing over the EstLink 2 underwater cable as it stopped working,

Damage to the power cable in the Baltic Sea is the latest in a spate of murky disruptions to undersea cables that have put European authorities on high alert.