Germany said on Saturday the suspected sabotage of an undersea power cable linking Finland and Estonia this week was a “wake-up call” that demanded new EU sanctions against Russia’s “shadow fleet”.

The Estlink 2 cable that carries electricity from Finland to Estonia was disconnected from the grid on Wednesday, just over a month after two telecommunications cables were severed in Swedish territorial waters in the Baltic.

“Almost every month, ships are damaging major undersea cables in the Baltic Sea,” German Foreign Minister Annalena Baerbock said in a statement to the Funke media group.

“Crews are leaving anchors in the water, dragging them for kilometres along the seafloor for no apparent reason, and then losing them when pulling them up,” she said.

“It’s more than difficult to still believe in coincidences. This is an urgent wake-up call for all of us.”

Baerbock urged “new European sanctions against the Russian shadow fleet”, ships that transport Russian crude and oil products despite embargoes imposed over Moscow’s invasion of Ukraine.

The fleet is “a major threat to our environment and security” that is used by Russia “to finance its war of aggression in Ukraine”, she said.

Finnish authorities said on Thursday they were investigating the oil tanker, Eagle S, that sailed from a Russian port, as part of a probe into “aggravated sabotage” of the Estlink cable.

Nato will bolster its military presence in the Baltic Sea in response, the Western alliance’s secretary general, Mark Rutte, said on Friday.