The Silver Dania is the third ship detained in recent weeks over concerns of intentional damage to subsea infrastructure in the Baltic Sea.

Another undersea data cable, this time connecting Sweden and Latvia, has been severed in the Baltic Sea, officials from both countries said Sunday. The incident prompted Sweden to launch a criminal probe into the matter and seize a "suspect vessel" vessel headed for Russia.

Seven crew members of the seized ship Eagle S are being treated as suspects as Finland investigates undersea cable sabotage and alleged Russian spying.

The pictures show neatly trimmed fiber optic cables dug up from underground behind what appears to be a well-hidden grate. The apparent simplicity of the sabotage is all the more harrowing in light of how extensively it disrupted Internet service in France, experts said.