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.

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

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.