The fresh intelligence that led to yesterday's extraordinary terror alert comes from documents discovered after Pakistani and U.S. forces broke up an al Qaeda cell in Gujrat, Pakistan, eight days ago, U.S. intelligence officials said yesterday.

One of the men arrested in that raid led authorities to the documents, which contained the startling details of al Qaeda surveillance of corporate and government targets in Washington, New York and New Jersey.

Officials from several U.S. intelligence and law enforcement agencies huddled virtually round-the-clock Friday, Saturday and Sunday to discuss the fast-emerging information, government sources said, assembling intelligence from the arrested al Qaeda operatives and translating and culling through the documents.

"This is definitely a nail-biter," one law enforcement official said.

The information that emerged appears to confirm that al Qaeda continues to plan operations and conduct surveillance against targets inside the United States. It buttresses the warnings of law enforcement and intelligence officials that al Qaeda has operatives in the United States and that U.S. financial institutions -- particularly ones in New York and Washington -- remain favorite targets of the terror network.

The news also highlighted a victory for the CIA, which for several months has mounted campaigns, in coordination with allied foreign security agencies and U.S. Special Forces, to attack suspected al Qaeda strongholds in Pakistan, Afghanistan, Yemen, Somalia, and elsewhere in northern Africa.

It was unclear yesterday whether the new documents, which a senior U.S. intelligence official called "a treasure trove," were plucked from two laptop computers recovered from the hideout in Gujrat where the al Qaeda operatives were arrested after a shootout July 25. But Pakistani and U.S. intelligence officials had expressed great interest last week in the contents of the portable computers, computer disks and cell phones seized in the raid.

The joint Pakistani-U.S. raid netted Ahmed Khalfan Ghailani, a Tanzanian wanted for his alleged role in the 1998 bombings of U.S. embassies in Kenya and Tanzania, as well as five other Pakistani and African al Qaeda suspects. U.S. intelligence sources said the most important new information came not from Ghailani but from one of the other al Qaeda associates, who led them to the cache of documents in recent days.

Senior intelligence officials said yesterday that they do not have al Qaeda cells under surveillance in this country that might have intended to carry out the planned terrorist attacks. Homeland Security Secretary Tom Ridge said a woman arrested at a Texas airport has no apparent link to the surveillance, though she remains under investigation.

Senior U.S. intelligence officials interviewed yesterday stressed that although the new documents reveal a great deal about the plot against the Citigroup Center in Manhattan, the World Bank in Washington and other financial institutions, equally valuable insights were gained about how al Qaeda operates in the United States and around the globe.

"This greatly advances our understanding of the al Qaeda leadership that has slowly been coming into focus," one ranking intelligence official said. "It gives us a specificity . . . that we've never seen before."

Another senior U.S. intelligence official said the new information comprises a virtual playbook of the tradecraft al Qaeda surveillance teams use. It details, for example, the use of phony couriers and delivery people to get inside the buildings, intelligence officials said.

It also provides fresh insight into the roles of high-ranking leaders who provide overall direction and facilitators who handle logistical details.

Intelligence officials said the al Qaeda surveillance began before the Sept. 11, 2001, attacks and continued perhaps until recent months.

"This confirms what everybody has known for a long time, that al Qaeda operates on a very long lead time," said Bruce Hoffman, a terrorism specialist with the Rand Corp. "It's also proof of their resilience, since they were able to be doing this even after all that U.S. intelligence and law enforcement has done for the three years after 9/11."

Surveillance, the first stage of a planned terrorist attack, is followed by planning and operational phases, Hoffman said. "The challenge now," he added, "is to determine when in the attack cycle al Qaeda is. . . . Are the planning and operational cells here also?"

The new information comes amid a summer of warnings from government officials that al Qaeda hopes to disrupt U.S. elections by attacking before November, or possibly around the time of the presidential inauguration in January. But U.S. intelligence officials said yesterday that they are uncertain whether the planned attacks on the financial targets were intended for coming months.

Word of the intelligence bonanza came as the Bush administration prepares to release its proposals for reforming the intelligence community in response to the Sept. 11 commission's report.

The information was given to top intelligence officials Thursday at the regular 5 p.m. meeting in the director of central intelligence's conference room at CIA headquarters, chaired by John E. McLaughlin, the acting DCI.

With representatives around the table from CIA counterterrorism units, the FBI and the Pentagon, operational plans for surveillance and arrests at home and abroad were developed. "There are a whole raft of operations going on right now overseas as well as at home," a senior intelligence official said yesterday. President Bush was briefed aboard Air Force One on Friday morning.

Staff writer Susan Schmidt contributed to this report.