MORE than 250 people were feared dead today after an airliner crashed into New York two months and a day after the September 11 suicide hijackings.

The American Airlines Airbus A300 plunged nose first into the borough of Queens less than ten miles from John F Kennedy airport, turning a residential area into an inferno.

The cause of the tragedy, which brought air crash horror to New York once more, was not immediately clear.

An engine fell from the jet moments before impact and eyewitnesses said the wings were going backwards and forwards "like it was trying to balance itself".

Bush administration officials said the FBI believed there was an explosion on board the plane and its cause was under investigation.

But the US Federal Aviation Authority said there was no immediate evidence the crash was a result of a terrorist attack.

The city's three commercial airports were closed and military jets patrolled the clear skies above the city. Some bridges and tunnels were also shut.

Mayor Rudolph Giuliani, who just two months ago was at the wreckage of the World Trade Centre, said the shut down was a precaution.

Flight 587 en route from New York to the holiday island of the Dominican Republic plunged into the ground just after take off, wrecking buildings and throwing up a huge pall of smoke.

The crash happened at about 9.15am local time (2.15pm UK time).

Mayor Giuliani said one of the engines had fallen from the jet.

"The first thing that went through my mind was oh my God'," Giuliani said.

Up to 12 buildings were said to be on a fire in the area of the crash.

There were 246 passengers and nine crew on board.

Eyewitnesses described large amounts of "smoke" and disbelief from the public.

Shares slumped in the minutes after the crash.

At 2.37pm the FTSE 100 Index was down 178.9 points at 5065.3, after being down around 30 points at lunchtime.

In the US, the Dow Jones industrial average also tumbled, falling 171.67 points at 14.38pm to 9436.33.

Shares in airline stocks were impacted heavily, with British Airways falling 13% and airports operator BAA down 5%.

Prime Minister Tony Blair, speaking at Downing Street just minutes after hearing reports of the crash, said: "We have regrettably just heard reports of an airliner that has gone down in New York.

"We simply don't know any more details than that at the present time.

"All I want to say at this juncture is that our thoughts and prayers are with the families of the victims and with the American people at this time.

"I don't think it is sensible for us, on the basis of the information we have, to speculate any further."

Cinny Kennard, who was at JFK waiting for a flight to Los Angeles when the plane crashed, said the reaction in the airport was one of "Oh no, not again".

People had rushed to phones and computer terminals to call or e-mail loved ones to tell them they were safe, she said, but added that the atmosphere was "solemn".

Witness Eddie Niedes said he saw an engine on the wing blow up seconds before the plane plunged to the ground.

"It was flying fine with no problems. It seemed to be on a normal flightpath.

"Then the engine on the right side blew up and it went straight down into a nosedive. There were flames on the right hand side.

"It was very fast. I don't think the pilot had any choice but to go straight down."

He added: "It was very, very frightening. I was watching the plane from my office all the way along and it blew up right in front of my eyes."

Beverly Browne, from Brooklyn, said she saw white smoke coming from the plane before it crashed.

"The wings were going backwards and forwards like it was trying to balance itself. There was white smoke coming out of it.

"It just couldn't seem to stabilise itself.

"The next thing I knew it had crashed."

Susan Locke, who lives a few blocks away from the crash, said she saw it coming "straight down" in the middle of a residential housing area.

"I didn't hear an explosion. I heard a rumble that shook my house. I looked out and saw it go straight down.

"I didn't see any smoke. It wasn't coming down on its belly, but nose down. It might not have been at 90 degrees but it was certainly head first."

The crash site is densely populated with lots of small homes. There is also a school nearby, which luckily was closed for veterans' day, according to reports.

Forty four fire trucks were at the scene. The Airbus came down in a residential neighbourhood right under the JFK airport flight path.

Mr Giuliani appealed for people to stay calm, saying President George Bush was "on top of it".

Mr Giuliani added: "We asked for air cover. The airports have been closed for a while, just for a precaution.

"We should really focus all of our efforts on trying to see if we can find survivors."

The tunnels linking different boroughs of the city were being closed as a precaution, Mr Giuliani said.

"We are sensible and we understand what happened before, so for a while the city's going to be on an even higher level of security," he said.

Mr Giuliani said the Rockaway area had been hard hit by the World Trade Centre attacks and added: "I passed a church where I have been for I think 10 funerals.

"I have been here probably 20 times for funerals and wakes so the idea that Rockaway could be the victims of this is terrible.

"We will do everything we can to help these people."

He went on: "We should remain absolutely calm. We are just being tested one more time. We will pass this too.

"The firefighters and police are the best in the world at this."

Wreckage from the jet, which appeared to be part of the engine, littered a street some distance from where the plane came down, lending weight to reports that it came apart in mid-air.

Emergency workers cordoned off large sections of the area as they searched for any possible survivors and tried to fight the fire caused by the crash.