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.
The Cook Islands-registered Eagle S was boarded by Finnish police and coastguard officials on Thursday and sailed into Finnish waters where the crew of the impounded tanker is being questioned.
A break in the 658 megawatt (MW) Estlink 2 power cable between Finland and Estonia took place at midday on Wednesday, leaving only the 358 MW Estlink 1 linking the two countries, grid operators said.
They said Estlink 2 might not be back in service before August.
Finnish police suspect the Eagle S caused the damage by dragging its anchor along the seabed.