Eleven people have been found dead and two are missing after a helicopter crashed west of the Norwegian city of Bergen with 13 on board, rescuers say, BBC reported.
Photos from the scene show thick smoke coming from an area of rocky islets.
The helicopter was "totally destroyed", reports said. It was flying from the Gullfaks oil field to Bergen, a centre for the North Sea oil and gas industry.
The helicopter, a Eurocopter 225, came down near the small island of Turoey, just west of the village of Solsvik.
Police spokesman Morten Kronen said a major rescue operation was under way, which included firefighters, divers and medical workers.
Eyewitnesses reported seeing the helicopter's rotor blade come loose and shear off.
"There was an explosion and a very peculiar engine sound, so I looked out the window. I saw the helicopter falling quickly into the sea. Then I saw a big explosion," a local resident told local newspaper Bergensavisen.
Some wreckage was found on the island, and parts of the hull are in the sea, local media said.
All passengers on the helicopter were employees of the oil company Statoil, reports say.
Service company CHC Helicopter confirmed that there had been "an incident involving one of our aircraft in the Norwegian sector".
Statoil has temporarily grounded all helicopters of the same type.
