A helicopter has ditched in Atlantic waters off Canada’s easternmost province of Newfoundland, reports say.
A local rescue co-ordinator told news agencies that 18 people were on board at the time of the incident.
Jeri Grychowski said one survivor had been lifted from the freezing water, but the fate of the other 17 remains unknown at present.
A search-and-rescue operation is under way, involving military and civilian aircraft and ships.
The helicopter was said to have been ferrying workers to the Hibernia offshore oil platform.
It reportedly ditched 47 nautical miles (54 miles; 87km) south-east of St John’s, capital of Newfoundland.
Ms Grychowski - of the Rescue Co-ordination Centre in Halifax - earlier said two people had been spotted in the water. One person is now thought to have been rescued and taken to hospital.
Mechanical problems were reported but we don’t know the nature
Transportation Safety Board of Canada
A life raft was also seen, though it was not clear whether anyone was inside it. There was no sign of the helicopter.
“We’re still actively searching,” Ms Grychowski told the BBC. She said winds were fairly strong in the area, with 1.8m-2.7m (6-9ft) waves.
The rescue centre said a mayday call had been issued just before 0800 EST (1300 GMT).
“Mechanical problems were reported but we don’t know the nature,” Julie Leroux, of the Transportation Safety Board of Canada, told AP news agency.
A local health official said the emergency room of a St John’s hospital was being prepared for “critically ill or hypothermic people”.
Those aboard the helicopter are thought to have been oil workers.
“It’s a shuttle service between Hibernia and St John’s, Newfoundland,” Ms Grychowski said.
“It moves passengers from the mainland to the Hibernia oil rig, which is about 170 nautical miles from the mainland.”
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