In just three months, three incidents of damage to Baltic Sea underwater cables have taken place. While accidential cable slices are common, the cluster raises suspicion.

Estonia’s defence minister proposed on Wednesday that shipping companies may have to pay a fee to use the Baltic Sea, one of the world’s busiest shipping routes, to cover the high costs of protecting undersea cables following a series of breaches,

The Silver Dania cargo ship, a Norwegian vessel with an all-Russian crew, was boarded at the request of Latvian authorities with the help of coastguard, police said.

Nato countries have stepped up patrols to protect critical underwater infrastructure in the Baltic Sea, which is bordered by eight countries, and other waters. A Royal Navy submarine was ordered to surface last November close to a suspected Russian spy ship which was loitering over undersea infrastructure in UK waters.

After a series of suspected undersea cable cuttings, NATO has launched a new surveillance and deterrence mission to protect critical infrastructure under the Baltic Sea.

NATO is ratcheting up its guard against suspected attempts to sabotage underwater energy and data cables and pipelines that crisscross the Baltic Sea.

The authorities said they believed the vessel may have been involved in damaging the cable, the latest act of apparent sabotage in the Baltic Sea.