Bush administration officials said the Federal Bureau of Investigation believed an explosion occurred aboard the jet, and witnesses reported hearing one and seeing an engine fall off. Investigators suggested the noise was caused by a catastrophic mechanical failure, and a senior administration official, speaking on condition of anonymity, said: ''It's looking like it's not a terrorist attack.'' A White House spokesman declined to rule terrorism in or out as a possible cause of the crash but said he would not dispute the assessment of U.S. officials, speaking on condition of anonymity, who said there was no preliminary evidence of terrorism.

Still, the city-on edge after the September 11 attack in which hijacked airliners brought down the World Trade Center-was put on high alert in the minutes and hours after the crash.

All metropolitan-area airports - Kennedy, LaGuardia and Newark, New Jersey - were closed, and international flights were diverted to other cities. Bridges and tunnels were closed to incoming traffic. The United Nations was partially locked down, and the Empire State Building was evacuated.

The stock market reflected the economic concerns that terrorism has produced. Wall Street's losses were spread across most sectors and industries, but among the biggest losers were airlines and the companies that supply them. Leisure-related stocks also suffered as investors worry that skittish consumers will take fewer vacations. Security companies were among the gainers. Losses were not confined to the United States. They widened in Europe as well following the crash in New York City.

This sad event has underscored the fear that terrorism has imposed not only on the United States but on the world. Most of the passengers aboard the plane were from the Dominican Republic. Relatives of passengers aboard American Airlines Flight 587 crowded the airport, weeping and hugging each other after hearing the flight bound for the Caribbean nation crashed shortly after takeoff Monday.

How has the crash in New York City affected the deliberations of the Fourth Ministerial WTO conference in Qatar? Even before the crash, our correspondent in Qatar, Reem Haddad, reported on the subject that is dominating the world: terrorism. "It's there. The question hangs in the air. But few agree to give answers. Several shake their heads with a knowing smile. I don't want to talk about it." Haddad then posed the most pertinent question: "Can the WTO by removing trade barriers which may eventually lift a country from poverty-solve the problem of terrorism?" By itself, that might not relieve the world of the scourge of terrorism has imposed on all of us, but it would surely help.

on the ground. Four houses were destroyed, four were seriously damaged, and as many as a dozen others sustained lesser damage.

Bush administration officials said the Federal Bureau of Investigation believed an explosion occurred aboard the jet, and witnesses reported hearing one and seeing an engine fall off. Investigators suggested the noise was caused by a catastrophic mechanical failure, and a senior administration official, speaking on condition of anonymity, said: ''It's looking like it's not a terrorist attack.'' A White House spokesman declined to rule terrorism in or out as a possible cause of the crash but said he would not dispute the assessment of US officials, speaking on condition of anonymity, who said there was no preliminary evidence of terrorism.

Still, the city-on edge after the September 11 attacks in which hijacked airliners brought down the World Trade Center-was put on high alert in the minutes and hours after the crash.

All metropolitan-area airports- Kennedy, LaGuardia and Newark, New Jersey-were closed, and international flights were diverted to other cities. Bridges and tunnels were closed to incoming traffic. The UN was partially locked down, and the Empire State Building was evacuated.

The stock market reflected the economic concerns that terrorism has produced. Wall Street's losses were spread across most sectors and industries, but among the biggest losers were airlines and the companies that supply them. Leisure-related stocks also suffered as investors worries that skittish consumers will take fewer vacations. Security companies were among the gainers. Losses were not confined to the US. They widened in Europe as well following the crash in New York City.

This sad event has underscored the fear that terrorism has imposed not only on the US but on the world. Most of the passengers aboard the plane were from the Dominican Republic. Relatives of passengers aboard American Airlines Flight 587 crowded the airport, weeping and hugging each other after hearing the flight bound for the Caribbean nation crashed shortly after takeoff Monday.

How has the crash in New York City affected the deliberations of the Fourth Ministerial WTO conference in Qatar? Even before the crash, our correspondent in Qatar, Reem Haddad, reported on the subject that is dominating the world: terrorism. "It's there. The question hangs in the air. But few agree to give answers. Several shake their heads with a knowing smile. I don't want to talk about it." Haddad then posed the most pertinent question: "Can the WTO by removing trade barriers which may eventually lift a country from poverty, solve the problem of terrorism?" By itself, that might not relieve the world of the scourge of terrorism has imposed on all of us, but it would surely help.