A Norwegian cargo vessel with a crew of six is believed to have sunk in Swedish waters close to the town of Stromstad after a severe storm.

Birger Knutsson, rescue operation leader at Sweden's Maritime Rescue Coordination Centre, said searchers found life vests, lifeboats and debris but no ship and none of the crew, believed to be Russian.

'We received an emergency signal via satellite, we sent a unit to the location, which found debris, life vests and lifeboats,' Mr Knutsson said.

The Norwegian-registered Langeland, carrying stone to the Norwegian city of Moss, sent the signal for help close to the Koster islands on the Swedish North Sea coast near Norway.

The storm also caused a Chinese-owned dry-bulk vessel to run aground in Norway, where it is leaking fuel.