The Finnish authorities said the tanker might be part of Russia’s shadow fleet, which emerged as a way to circumvent Western-imposed price caps on Russian oil transported by sea. The caps were introduced several months after President Vladimir V. Putin of Russia ordered the full-scale invasion of Ukraine in February 2022.

Police and media reports say that Finnish authorities have detained a Russia-linked ship as they investigate whether it damaged a Baltic Sea power cable and several data cables.

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.