Updated

The United Nations closed off its headquarters to pedestrians and vehicles as news of the plane crash in New York City on Monday stunned ministers from member nations who gathered here for the annual General Assembly debate.

"Terrible," said U.N. Assistant Secretary of State Danilo Turk, shaking his head as he rushed into a meeting of officials from the United States, Russia and Afghanistan's six neighbors to discuss a post-Taliban government.

Shocked diplomats stood in the corridors watching television screens showing smoke rise from the crash site.

U.N. security chief Michael McCann went on the public address system at the U.N. headquarters in New York city to announce the crash.

As a precautionary measure, McCann said, all vehicles and pedestrians have been barred from entering U.N. headquarters, but said: "We have decided not to evacuate the complex at this time," he said.

Speeches in the General Assembly continued, but ministers were clearly affected by the crash.

"My condolences to all the lives that seem to be lost again in New York," said Turkey's Foreign Minister Ismail Cem, whose speech was interrupted by the security chief's announcement.

Germany's Foreign Minister Joschka Fischer, who spoke next, said: "We're shocked and horrified, and to the relatives the families and the American people, I would like to express our sincere condolences."

Jamaica's U.N. Ambassador Patricia Durrant, the current president of the Security Council, told reporters before an open council meeting: "I have been asked by the Security Council to express our sincere and heartfelt sympathies to the people and the government of the United States and the families of those who have lost their lives."

Security has been tightened at the landmark 39-story U.N. headquarters building, which was reported to be a terrorist target after the 1993 bombing of the World Trade Center.

The road in front of the headquarters has been closed to traffic since the Sept. 11 attacks, though authorized vehicles had been allowed in. Authorities had also closed the East River next to the building to maritime traffic as government leaders began gathering here for the weeklong meeting on Saturday.

Earlier this month, terrorist suspect Osama bin Laden attacked the United Nations and called Secretary-General Kofi Annan, winner of this year's Nobel Peace Prize, a "criminal."

The American Airlines jetliner on its way to the Dominican Republic with 255 people aboard crashed Monday moments after takeoff from Kennedy Airport in a residential neighborhood, setting homes on fire. Bush administration officials said the FBI believed there was an explosion aboard the plane, and was investigating whether it was the result of a mechanical failure or sabotage.