New York on high alert

The UN has been sealed off

An already tense New York went on high alert Monday following the crash of an American Airlines airbus in the city.

Every airport in the area - Kennedy, LaGuardia and Newark, New Jersey - was closed for several hours and planes were diverted elsewhere.

Rescue workers at the scene

The United Nations headquarters, where hundreds of senior government officials and a number of heads of states are attending the annual general debate, was sealed off with people being allowed out, but no-one allowed in.

The BBC's Richard Lister says road closures in the area resulted in severe gridlock.

A level-one alert was issued to call on emergency vehicles to get to the crash site as soon as possible.

Bridges, tunnels closed

All bridges and tunnels into the city were also closed, except to rescue workers, for a number of hours.

Fighter jets flew over the area.

Security at the UN headquarters, which is across the river from the crash site, has been tight ever since the terrorist attack on the city on 11 September, but security officials ruled out evacuating the building.

The BBC's UN correspondent, Greg Barrow, says UN officials are extremely concerned that the United Nations could be attacked following comments by the al-Qaeda leader Osama Bin Laden in which he attacked the UN as an organisation and criticised its Secretary-General, Kofi Annan.

But US officials stressed that there was no evidence that Monday's plane crash was the result of terrorism.

A senior administration official said no threats against airplanes had been received and that the pilot of Flight 587 reported no trouble before the crash.

But intelligence agencies, the FBI and the Federal Aviation Administration are reported to be reviewing all recent intelligence for any clue that terrorism was involved.