In a statement, the airline said: "All 215 passengers and 14 crew members died in the crash."

The McDonnell Douglas MD-11 was en route from New York's John F Kennedy Airport to Geneva when it plunged into the water at night.

Local authorities said weather in the area had been good, with clear skies and relatively calm seas.

The BBC's Rob Watson: "The evidence points to mechanical failure"

Helicopters joined coastguard and fishing vessels in a floodlit search of the wreckage near Peggy's Cove, a small fishing village about 64km (40 miles) south of the provincial capital, Halifax.

But as dawn broke hopes of finding any survivors had faded. At least 38 bodies have been recovered from the water, but the search is being hampered by increasingly choppy seas and strong winds.

Divers are being used to search for the plane's "black box" flight recorder.

UN officials among the dead

A distraught relative is comforted at Geneva airport

Swissair said 136 of the passengers on Flight 111 were US citizens.

The remainder included: 30 French, 28 Swiss, six Britons, three Germans, three Italians and two Greeks.

There was also one passenger from each of: Saudi Arabia, Yugoslavia, Afghanistan, Iran, Spain, St Kitts and Russia.

BBC Aviation Correrspondent Christopher Wain: What could have caused the crash

Fifty three passengers of the American airline Delta and one Delta crew member were onboard under a flight-sharing arrangement with Swissair.

The United Nations has announced that between six and 10 officials from UN offices around the world were on the flight.

Watch BBC Aviation Correspondent Chrisopher Wain's report on the crash

It is believed that a high-ranking former head of the World Health Organisation's Aids programme, Jonathan Mann, and his wife, both Americans, were on the flight.

The Director-General of the UN in Geneva, Bladimere Pritroski, said that he was profoundly shocked by the tragedy and that the UN flag would fly at half mast from Friday.

Phone lines have been set up for people who believe they may know somebody who was on the plane.

Relatives of the dead who went to the airports in Geneva and New York were offered counselling.

Planes are also being laid on to transport them from Geneva and Zurich to Halifax on Thursday night.

Smoke in cockpit

Aviation expert Eric Moody: what happens when there is smoke on an airliner

Shortly before the crash the pilot made a request to make an emergency landing at Halifax airport.

He reported smoke in the cockpit, before losing radio contact with air traffic controllers.

The plane disappeared off the radar screen at about 0230 BST on Thursday, approximately one hour after take-off. It reportedly dumped tons of fuel along the shoreline before crashing.

Local people volunteered to join the search

People living near the crash reported seeing a very low flying aircraft followed by a loud noise.

A local woman spoke of hearing a plane moments before her house shook "as if something had bumped into it". Another said she had heard a big explosion.

The Swiss Transport Minister, Moritz Leuenberger, said the smoke on the plane could have come from one of the engines, from the hold where freight is stored or from an electrical failure.

Crash investigator Roy Bears describes the last moments of Flight 111

A team of crash investigators is now on its way from Switzerland to help Canadian officials.

The Executive Vice President of Swissair, Georges Schorderet, said the plane had been in a "perfect working state". It was too soon to say exactly what had gone wrong, he said.

The Vice President of the airline, Walter Vollenwieder, said the company had not withdrawn its other MD-11 planes from service after the crash.

"There wasn't any reason to," he said.

National mourning

Sair Chief Executive Philippe Bruggisser: "Our thoughts are with the relatives."

The Swiss President, Flavio Cotti, expressed his deepest sympathy to families of the victims and said Swiss flags would be flown at half mast as an expression of grief.

"This is a difficult day for us all and for our country," he said.

Flags at half mast at the Swiss Federal Parliament in Bern

Swissair has one of the world's best safety records, and the crash is its first disaster to hit it since October 1979 when a DC-8 carrying 142 people crashed into a fence while landing at Athens airport, killing 14 people.