The Swedish coast guard seized a Bulgarian ship after a fibre-optic cable under the Baltic Sea linking Sweden to Latvia was damaged, officials said on Monday. The damage to the cable occurred in Swedish territorial waters at a depth of at least 50 metres (164 feet),

The Nordic country has opened an investigation into the damage, just weeks after NATO stepped up its military presence in the area following a series of similar incidents.

Norwegian police have arrested a ship suspected of damaging a telecoms cable between Latvia and Sweden last weekend, according to the Norwegian public broadcaster NRK.