LONDON (AFP) - Four people were confirmed dead after a helicopter transporting employees from an oil rig crashed off the Scottish coast, the police said on Saturday, in the latest in a series of air incidents in the North Sea oilfields.
French oil giant Total said the dead were all from contractor organisations. The helicopter was operated by Canadian-based aviation company CHC.
The Super Puma L2 helicopter was travelling from the Borgsten Dolphin platform to Sumburgh airport on Shetland island when it came down 3km west of its destination on Friday.
Fourteen people, including two crew members, were rescued from the sea and taken to hospital.
"Police Scotland can confirm that four people have died after a helicopter went down in the North Sea near Shetland on Friday, 23 August, 2013," said a statement.
"The bodies of three people have been recovered and work is under way to recover the body of the fourth person."
The victims were named as Mr Duncan Munro, 46, Ms Sarah Darnley, 45, Mr Gary McCrossan, 59, and Mr George Allison, 57.
Ms Amanda Smith, the mother of one of the rescued people, Mr Sam Smith, told Britain's Sky News that her son described how the helicopter "seemed to lose power and there was no time to brace - they just dropped into the sea".
"He was by the window so he was able to escape that way as it rolled over," she said.
"He said he had come off better than a lot of people, were his words. It doesn't seem real."
Rescuers in dinghies could be seen recovering parts of the helicopter from churning water at the foot of a cliff, in video footage provided by the Royal National Lifeboat Institute (RNLI) and filmed from a rescue helicopter.
RNLI rescue coordinator Jim Nicholson said there appeared "to have been a catastrophic loss of power which meant the helicopter suddenly dropped into the sea without any opportunity to make a controlled landing".
CHC, which is based in Vancouver, Canada, said it was temporarily suspending all flights worldwide by its Super Puma fleet as a precaution.
"We do not know the cause of the incident. A full investigation will be carried out in conjunction with the UK Air Accident Investigation Branch (AAIB)," it said in a statement.
The AAIB confirmed it had sent a team of investigators to the area.
The Super Puma L2 is manufactured by Eurocopter, part of the European aerospace giant EADS.
Total said it had sent its own emergency response teams to the accident site.
"Total E&P UK would like to offer sincere condolences to the families of those who tragically lost their lives," the oil company said. "Our thoughts are also with the 12 other passengers and two air crew who were also on board the flight, and their families."
Scotland's First Minister Alex Salmond said: "It is still too early to know what caused this terrible tragedy, but a full investigation by the relevant authorities is already under way."
There has been a series of incidents involving helicopters in the North Sea. In May, all 14 people on board a Super Puma helicopter were rescued after it ditched off the coast of Aberdeen.
Another helicopter ditched in the North Sea last October, but all 19 people on board survived.
Sixteen men died when a Super Puma helicopter plunged into the sea after its gearbox failed as it was flying from BP's Miller platform to Aberdeen in April 2009.