A Norwegian-registered cargo ship has sunk off the west coast of Sweden with six crew members onboard, maritime officials said on Friday.

The ship, named Langeland, got into difficulties after being battered by stormy weather off the coast close to the Swedish town of Strömstad.

"This morning at 06:00 (0400 GMT), we received a distress signal from the Langleland vessel indicating it had problems," said Dan Nicklasson, a captain with the Swedish coastguard in Gothenburg.

Nicklasson said a search was underway for the ship's six crew members, but admitted that "time was running out" for them to be found alive.

Meanwhile, maritime authorities in Russia released a statement saying the ship's crew was made up Russian and Ukrainian nationals.

"No bodies have been found as yet. We have a helicopter and aircraft searching the area now. We found life rafts and wreckage from the ship. We also found patches of oil," added Christer Fjällström, a duty officer for the Swedish coastguard.

The 2,500-tonne, 70-metre long Langeland was on its way to the port of Moss in western Norway and was carrying a cargo of stones, maritime officials said in a statement.

In a seperate incident on Friday, a Panama-registered cargo ship ran aground off Norway's south coast, causing an oil spillage.

Norwegian authorities said the Full City ran aground at 00:30 CET (2230 GMT Thursday), just west of the town of Larvik, 132 kilometres (90 miles) south of Oslo.

All the 23 crew members were Chinese and 16 have already been evacuated by helicopter, a Norwegian rescue services spokesman said.

Nils Ole Sunde, a duty officer with the Norwegian coastguard, said the vessel was leaking oil after running aground on some rocks one kilometre (0.6 miles) from the coast.

Sunde added that seven crew members were still on board but were not in any immediate danger.

"The ship is rather stable at the moment. We have no reason to believe that she will sink in the near future. The wind is not so strong anymore and the sea is calming," he said.

Sunde told AFP the Full City had been carrying 1,120 tonnes of oil at the time but had no other cargo.