Sweden sent a submarine rescue vessel to assist Finland in the investigation last week.

"The HMS Belos has located and lifted the anchor and handed it over to Finnish authorities," Swedish navy spokesman Jimmie Adamsson told AFP.

The Eagle S, flying the Cook Islands flag, is suspected of having damaged the EstLink 2 electricity cable between Finland and Estonia in the Baltic on December 25, putting it out of action.

Finnish police said on December 29 that they had found a trail from the anchor stretching dozens of kilometres (miles) along the seabed.

The national energy agency Fingrid said it had requested that authorities seize the tanker.

Finnish authorities have banned eight crew from leaving Finnish territory. Finnish customs have said they suspect the tanker, currently located east of Helsinki, is part of Russia's so-called "shadow fleet" -- ships that carry Russian crude oil and petroleum products that are embargoed over Moscow's invasion of Ukraine.

Finnish telecom operator Elisa said Monday that two of the damaged telecom cables had been repaired. The Estlink 2 power cable has not yet been repaired.

According to operator Cinia, one of the remaining telecoms cables -- running between Finland and Germany -- should be fixed by January 10.

In late December, NATO announced it would strengthen its military presence in the Baltic after similar incidents there since Russia's 2022 invasion.

Energy and communications infrastructure in particular have been targeted as part of what experts and politicians call Russia's "hybrid war" with Western countries.

The Baltic is surrounded by a number of NATO member states.

Two telecommunications cables were cut on November 17 and 18 in Swedish territorial waters.

A Chinese-flagged bulk carrier, the Yi Peng 3 is suspected of involvement.