White House spokesman P J Crowley said in Washington, ``We have no indication that terrorism was involved.''

Search and rescue centre spokesman Dan Bedell said on phone: ``No survivors have been found and 18 bodies have been recovered so far,''.

The MD11 jet en route from New York to Geneva with 215 passengers, including two infants and 14 crew, on board was trying to land at Halifax airport when it crashed off the southern coast of Nova Scotia at 7 am, officials said.

The pilot reported smoke in the cockpit before losing contact with Halifax Air Traffic Controllers about an hour and 40 minutes after take-off, the Canadian press agency said.

But neither rescue officials nor transport officials could confirm the report.

In Switzerland, chief executive of Swissair parent company Sairgroup,said he feared all passengers were killed. ``We expect no survivors,'' he told reporters at Zurich.

But rescue workers scouring the icy Atlantic waters about 13 km off Peggy's Cove on Nova Scotia's south shore, some 50 km from Halifax, refused to give up hope.

``First and foremost we are looking for survivors. We have not given up hope,'' an official said.

Most of those killed in the worst ever plane crash in over three decades were locals and UN officials. Some passengers of Delta Airlines were also in the Swissair flight under a code-sharing agreement.

Foggy weather and choppy seas were hampering rescue efforts, rescue officials said.

A flotilla of boats -- a dozen military aircraft, two warships and dozens of Canadian coast guard vessels and fishing boats -- were still combing the seas for survivors.

A rescue official described the mood at the scene as ``gloomy'' with the sea dotted with debris from the ill-fated aircraft, life jackets and bodies.

A Swissair spokesman said the ill-fatedplane was only seven years old, comparatively new by the standards of most US domestic passenger jet aircraft.

An airport worker said the pilot dumped 208 tonnes of fuel near St Margaret's bay before going down in a huge ball of fire off the coast of the popular tourist resort known for its picturesque coastline.

In Geneva, a Swissair official said the ill-fated plane tried to head for Boston but settled for Halifax as it was closer.

``He (the pilot) first asked for permission to land in Boston but decided against it because Halifax was closer,'' vice president for North and South America operations Walter Vollenweider said.

Several UN Staff were among those killed, UN sources said.