Finnish police said on Sunday they had found tracks that drag on for dozens of kilometres along the bottom of the Baltic Sea where a tanker carrying Russian oil is suspected of breaking a power line and four telecoms cables with its anchor.

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.

Finland has seized the Eagle S, a Cook Islands-flagged oil tanker, as part of an investigation into severe damage to underwater cables in the Baltic Sea.

NATO allies met on Dec. 30 to address the security of critical infrastructure in the Baltic Sea, following damage to undersea cables connecting Estonia and Finland several days earlier.

General Mark Rutte says the military alliance will step up patrols in the Baltic Sea area as Finnish investigators work to establish whether a ship linked to Russia sabotaged undersea cables there this week.

NATO member Estonia has deployed a naval warship to defend its underwater power cables after a Russian vessel allegedly cut one of the wires in yet another act of sabotage against the allied nations.

In Russia's view, both Hungary and A senior NATO official outlined the strong possibility of an unconventional attack by Russia on NATO countries in an interview with London-based broadcaster Sky News on Sunday.