Police say a Norwegian-owned and Russian-crewed ship that authorities suspect may have been involved in damage to an underwater fiber optic cable connecting Latvia and the Swedish island of Gotland has been stopped off Norway.

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.

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.

The NATO military alliance is ramping up efforts to protect undersea cables in the region amid growing concerns of Russian sabotage and spying. View on euronews

Baltic Sea as part of a mission to protect undersea cables and pipelines. As authorities investigate the fourth Baltic Sea cable-cutting incident in recent months, European leaders have expressed concern about the frequency of attacks involving civilian vessels and critical civilian infrastructure.