Search for Canada crash survivors
Earlier, rescue co-ordinator Jeri Grychowski said everything was being done to locate more survivors
One person has been rescued but 17 remain missing in icy waters after a helicopter crashed off Canada's easternmost province of Newfoundland.
The pilot of the S-92 Sikorsky helicopter had reported technical problems, Rick Burt, of charter Cougar Helicopters, told a news conference.
The pilot said he would turn back but he never arrived, Mr Burt added.
Military and civilian aircraft and ships are continuing to scour the area, where debris has been found.
The helicopter crashed 47 nautical miles (54 miles; 87km) south-east of St John's, capital of Newfoundland.
It had been ferrying workers from St John's to oil platforms in the Hibernia and White Rose oil and gas fields, some 200 miles (320km) and 217 miles respectively south-east of the Newfoundland coast.
The helicopter crashed on Thursday morning, in mild weather, Mr Burt told reporters.
"The aircraft was on its way out, experienced technical problems, radioed in that it was turning around and that was the last that we had communication," he said.
One person was rescued by a civilian helicopter also owned by Cougar, and taken to hospital in St John's - though there was no word on his condition.
A "debris field" had been identified on the surface of the sea, Maj Denis McGuire, from a rescue co-ordination centre in Halifax, was quoted as saying.
Two life rafts were also identified and rescuers were trying to ascertain whether anyone was inside them.
"This is a very difficult time," Mr Burt said.
The service provided by Cougar shuttles workers between St John's and oil rigs out in the Atlantic.
Cougar now says it has suspended all offshore flights until it knows the cause of the crash.
On 18 February, a helicopter ditched close to an oil platform in the North Sea - but all 18 people on board survived thanks to a "textbook" rescue which included use of a state-of-the-art rescue craft.