Norway confirmed 13 people died in a Statoil helicopter crash off the west coast of the country on Friday.
Earlier, rescue personnel had recovered the bodies of 11 people, but Norway said in an update two more people were presumed dead.
The helicopter that crashed was one of the many that service offshore oil platforms in the North Sea.
Statoil said the helicopter was coming from the Gullfaks B platform, a North Sea oil field operated by the Norwegian oil company.
Norwegian broadcaster NTB said there were 13 passengers aboard the copter when it crashed in fairly good weather.
Eleven of them were Norwegians while the others were a Briton and an Italian. The Eurocopter helicopter belonging to the CHC Helicopter Group was totally destroyed in the crash.
A few hours after the crash, rescue agencies confirmed 11 of the passengers were dead. Statoil said it set up an emergency center in Bergen following the accident. Eleven of the 13 people on board the helicopter were Statoil staff.
Norway's Civil Aviation Authority said the helicopter suffered technical faults in the past. "There have been challenges with this kind of helicopter model in 2012, when errors in the main gear box were identified... That model received flying restrictions in 2012 and 2013," the authority said, according to Reuters.
Statoil also said several Eurocopter helicopters had been temporarily taken out of service in the past, RT reported.
(The story was republished on 30 April with an updated death toll)