-- Intelligence developed from the capture of a key al Qaeda lieutenant five months ago helped lead to this weekend's arrest of reputed al Qaeda operations chief and Sept. 11 mastermind Khalid Sheik Mohammed, Pakistani authorities said today.

A series of arrests and interrogations in recent months, notably the capture of Mohammed's cohort, Ramzi Binalshibh, has pierced some of the secrecy surrounding al Qaeda, throwing the organization into disarray and forcing its leaders to go on the run, Pakistani police and intelligence officials said. Mohammed narrowly escaped arrest three times in the past five months, one official said.

U.S. authorities said they expect a trove of leads from the search of Mohammed's living quarters in the Pakistani city of Rawalpindi, and from interrogations he is undergoing at an undisclosed location outside Pakistan. Congressional intelligence committee leaders said they are hopeful Mohammed's capture will quickly lead authorities to other al Qaeda figures, including perhaps Osama bin Laden.

Even as they savored the long-sought arrest of one of the world's most dangerous men, U.S. law enforcement officials intensified their scrutiny of suspected al Qaeda sympathizers who may try to expedite their terror plans because they fear being exposed soon as a result of Mohammed's arrest. They are also concerned, they said, that the arrest will spur more al Qaeda violence.

FBI counterterrorism agents in this country are "working harder than ever, if that's possible," said a senior FBI counterterrorism official. Mohammed's capture, he said, is bound to have a huge impact on others in the organization. "It could go both ways -- it could send them to ground or it could activate a retaliatory strike," he said.

Everything found in Mohammed's living quarters will be immediately analyzed by the FBI for leads on other al Qaeda operatives or clues to planned attacks on U.S. interests.

"Computers, pocket litter, names, phone numbers -- it's all perishable information. You've got to move quickly to get that stuff," one source with long experience in counterterrorism said. "If there is a U.S. phone number, you've got to get on that quickly. There could be all kinds of records. If they get his black book, they'll be busy. There is just a ton of work to be done."

That sort of work is best done before an arrest is publicized, U.S. officials said, but in this case Pakistani authorities released the news right away.

Members of Congress who oversee the U.S. intelligence community predicted Mohammed's capture would quickly lead to more members of al Qaeda.

Rep. Porter Goss (R-Fla.), chairman of the House intelligence committee, called the arrest "a very huge event. This is the equivalent of the liberation of Paris during the second world war."

Appearing on ABC's "This Week," Goss likened Mohammed's importance to that of Joseph Goebbels, the top Nazi propagandist of Adolf Hitler. He said the arrest would give U.S. authorities "more focus and more clarity on exactly where to go and what to look at." He predicted "other very successful activities very shortly."

Goss, who has been briefed by intelligence officials on Mohammed's capture, said he believes Mohammed knows the whereabouts of bin Laden and has been in contact with him. He declined to say whether he had been told that by intelligence officials.

Sen. Pat Roberts (R-Kan.), chairman of the Senate intelligence committee, told "Fox News Sunday" the arrest would effectively put an end to a spring offensive officials believe al Qaeda was planning for Afghanistan.

"The idea behind this program is to go after the top 10," Roberts said. "We got the operations manager; more coming. Look out, al Qaeda. . . . It's a real coup for us. And I think there will be more coming."

After being put on the defensive by Democratic charges that the focus on Iraq could distract from the broader war on terrorism, White House officials reveled in the capture for what one official called "both its symbolism and its substance." They also said they expect it to lead to more arrests.

Authorities have also linked Mohammed to the 1993 attack on the World Trade Center, a failed plot two years later to blow up 11 U.S. airliners, and since Sept. 11, 2001, the bombing of a synagogue in Tunisia that killed 21 people. Another prisoner has accused Mohammed of killing Wall Street Journal reporter Daniel Pearl last year.

U.S. officials say Mohammed is a key conduit to al Qaeda networks in Asia, Europe and the United States, and is behind the round of threats that put the nation on high alert status last month.

Mohammed spent time in Hamburg, Germany, with the members of the Sept. 11 hijacking cell, and he took credit for organizing them.

Terrorism experts said they expect a spike in al Qaeda chatter picked up by intelligence operations, as operatives around the globe communicate with one another about whether they or their plans have been compromised.

"I'm sure his closest lieutenants are on the move," said Magnus Ranstorp, an internationally known terrorism expert at St. Andrews University in Scotland. "They will spend more time worrying about their security than planning a spectacular attack."

But, Ranstorp cautioned, "there are contingency plans whenever someone is arrested. . . . There are people willing to step in and fill his shoes."

U.S. officials declined to say where Mohammed was taken for interrogation. Other high-value captives, including Binalshibh, have been turned over to intelligence services in Arab countries allied with the United States in its war on terror, such as Jordan, Egypt and Morocco.

U.S. officials decided before the arrest that they would not seek to bring Mohammed to trial in the United States, said a source knowledgeable about the decision. They say getting Mohammed's information is more important than bringing him to justice in U.S. courts.

Authorities have been anticipating the capture for months. U.S. and Pakistani agents "were on [Mohammed's] tail since the arrest of Ramzi . . . who was Mohammed's right-hand man," a Pakistani intelligence official said.

"At least thrice in the past five months, we went close to Mohammed's arrest. But each time, he either managed to dodge us or the luck helped him out," he said.

Since agreeing to support the United States in its anti-terrorism campaign and its military operation in Afghanistan in the fall of 2001, the Pakistani government has handed over about 300 al Qaeda suspects to U.S. authorities, officials here say.

Binalshibh, a former roommate of al Qaeda suicide pilot Mohamed Atta, has been described as the planner of several attacks on U.S. and other Western targets inside Pakistan. He was apprehended in this port city on the first anniversary of the suicide attacks on the World Trade Center and the Pentagon, and Pakistani officials said his capture -- like that of Mohammed -- was made possible by an earlier raid.

"Abu Zubaida's arrest led to Ramzi's capture," the official said, referring to the apprehension of al Qaeda's top recruiter in Faisalabad, Pakistan, in March 2002. "Ramzi showed the way to Khalid Sheik Mohammed, and Mohammed may lead the Americans to Osama bin Laden and Ayman al-Zawahiri," bin Laden's top aide.

Interviews with Pakistani officials involved in coordinating with the FBI and the CIA in operations against al Qaeda and the Taliban revealed an increasing degree of optimism within the Pakistani intelligence community. In the words of one Pakistani official, al Qaeda "now stands disintegrated, with its commanders on the run."

Stressing that, to his knowledge, Binalshibh did not betray Mohammed while under interrogation, one official said that Binalshibh's capture "provided incredible intelligence and human sources on al Qaeda and its operations to the Americans."

The official acknowledged that after being given custody of Binalshibh by Pakistan's Inter-Services Intelligence agency within a few hours of his capture, U.S. agents have not shared all information obtained during his interrogation at an undisclosed location.

Pakistani officials confirmed today that, like Binalshibh and several other captured al Qaeda operatives, Mohammed was driven to Chaklala air base in Rawalpindi by Pakistani intelligence officials Saturday night. There he was handed over to the United States.

Schmidt reported from Washington. Staff writer Mike Allen contributed to this report.

Khalid Sheik Mohammed, shown shortly after his arrest, is being held at an undisclosed location.This house in Rawalpindi is the residence of a Pakistani man suspected of having al Qaeda links. Khalid Sheik Mohammed was arrested in the same city.Officials say they learned key information about al Qaeda after the arrest of Ramzi Binalshibh.