Finland's Elisa says Baltic undersea cables were torn apart by external force

Two undersea telecommunications cables that were damaged in the Baltic Sea on Dec. 25 appeared to have been torn apart by a strong external force, Finland's Elisa said on Monday, adding that they had now been repaired.

Baltic Sea nations are on high alert after a string of power cable, telecom link and gas pipeline outages since Russia invaded Ukraine in 2022. The NATO military alliance has said it will boost its presence in the region.

Finnish police seized the Eagle S tanker carrying Russian oil on Dec. 26 and said they suspected that the vessel had damaged the Finnish-Estonian Estlink 2 power line and four telecoms cables on Christmas Day by dragging its anchor across the seabed.

Sweden's navy on Friday sent a vessel equipped for underwater work to aid Finland's seabed investigation.

"The current suspicion is that the external force has been caused by an anchor," Jaakko Wallenius, Chief Security Officer at Elisa, which owns two of the four fibre optic lines, told Reuters on Monday.

The cables, running between Finland and Estonia, are steel-reinforced with a diameter of just over two centimetres, with several layers of insulation protecting the fibres within.

The Eagle S vessel, which is registered in the Cook Islands, was brought to a bay near Finland's port of Porvoo where police are currently collecting evidence and questioning the crew, eight of whom were named as suspects in the investigation.

A Finnish lawyer representing the company that owns the Eagle S has said Finland hijacked the vessel at sea and should release it, a request denied by a court on Friday.

Repairing the Estlink 2 power cable that was broken along with the telecoms cables is expected to take some seven months, operators Fingrid of Finland and Elering of Estonia have said.

Moscow has said Finland's seizure of the ship is not a matter for Russia.