The C.I.A.'s undercover New York station was in the 47-story building at 7 World Trade Center, one of the smaller office towers destroyed in the aftermath of the collapse of the twin towers that morning. All of the agency's employees at the site were safely evacuated soon after the hijacked planes hit the twin towers, the officials said.

The intelligence agency's employees were able to watch from their office windows while the twin towers burned just before they evacuated their own building.

Immediately after the attack, the C.I.A. dispatched a special team to scour the rubble in search of secret documents and intelligence reports that had been stored in the New York station, either on paper or in computers, officials said. It could not be learned whether the agency was successful in retrieving its classified records from the wreckage.

A C.I.A. spokesman declined to comment.

The agency's New York station was behind the false front of another federal organization, which intelligence officials requested that The Times not identify. The station was, among other things, a base of operations to spy on and recruit foreign diplomats stationed at the United Nations, while debriefing selected American business executives and others willing to talk to the C.I.A. after returning from overseas.

The agency's officers in New York often work undercover, posing as diplomats and business executives, among other things, depending on the nature of their intelligence operations.

The recovery of secret documents and other records from the New York station should follow well-rehearsed procedures laid out by the agency after the Iranian takeover of the United States Embassy in Tehran in 1979. The revolutionaries took over the embassy so rapidly that the C.I.A. station was not able to effectively destroy all of its documents, and the Iranians were later able to piece together shredded agency reports. Since that disaster, the agency has emphasized rigorous training and drills among its employees on how to quickly and effectively destroy and dispose of important documents in emergencies.

As a result, a C.I.A. station today should be able to protect most of its secrets even in the middle of a catastrophic disaster like the Sept. 11 attacks, said one former agency official. "If it was well run, there shouldn't be too much paper around," the former official said.

The agency's New York officers have been deeply involved in counterterrorism efforts in the New York area, working jointly with the Federal Bureau of Investigation and other agencies. Many of the most important counterterrorism cases of the last few years, including the bureau's criminal investigations of the August 1998 bombings of two United States Embassies in East Africa and the October 2000 bombing of the U.S.S. Cole in Yemen have been handled out of New York.

The United States has accused Osama bin Laden and his Al Qaeda terrorist network of conducting both of those attacks.

But United States intelligence officials emphasize that there is no evidence that the hijackers knew that the undercover station was in the World Trade Center complex.

With their undercover station in ruins, C.I.A. officers in New York have been forced to share space at the United States Mission to the United Nations, as well as borrow other federal government offices in the city, officials said. The C.I.A.'s plans for finding a new permanent station in New York could not be determined.

The agency is prohibited from conducting domestic espionage operations against Americans, but the agency maintains stations in a number of major United States cities, where C.I.A. case officers try to meet and recruit students and other foreigners to return to their countries and spy for the United States. The New York station, which has been led by its first female station chief for the last year, is believed to have been the largest and most important C.I.A. domestic station outside the Washington area.

The station has for years played an important role in espionage operations against Russian intelligence officers, many of whom work undercover as diplomats at the United Nations. Agency officers in New York often work with the F.B.I. to recruit and then help manage foreign agents spying for the United States. The bureau's New York office, at 26 Federal Plaza, was unaffected by the terrorist attack.

The destruction of the C.I.A.'s New York station has added to the intense emotions shared by many of its employees about the agency's role in the battle against terrorism. For some, the station's destruction served to underscore the failure of United States intelligence to predict the attacks.

In the immediate aftermath of the attacks, morale suffered badly within the C.I.A., some officials said, as the agency began to confront what critics have called an intelligence failure on the scale of Pearl Harbor.

But the terrorist attacks have also brought an urgent new sense of mission to the agency, which has been flooded with job applications as well as inquiries from former officers eager to return to work. Congress is pouring money into the agency's counterterrorism operations, and the C.I.A. seems poised to begin focusing its resources on terrorism in much the same way it once focused on the Soviet Union in the cold war.

The attacks were not the first in which the C.I.A. was directly touched by terrorists. In 1983, seven agency officers died in the suicide car bombing of the United States Embassy in Beirut. Among the others killed was the agency's station chief in Lebanon, William Buckley, who died in captivity after being kidnapped by terrorists in 1984, and Richard Welch, the agency's Athens station chief, who was shot to death by Greek terrorists in 1975.