Washington ? U.S. counterterrorism authorities, exploiting a trove of information gleaned from computers and other gear captured with al-Qaida chieftain Khalid Shaikh Mohammed, raced Sunday to identify individuals who they believe might be poised to launch attacks in the United States.

While interrogators worked urgently to pry information from the terror network’s operations leader, FBI agents in the United States and CIA operatives overseas urgently ran down leads pulled from several computers, computer disks, paper documents, cell phones and other electronic paraphernalia seized in a raid near Pakistan’s capital, Islamabad.

That joint Pakistani-U.S. raid before dawn Saturday at a home in Rawalpindi netted Mohammed, described by U.S. officials as one of the world’s deadliest terrorists and the mastermind of the Sept. 11 attacks, as well as two suspected al-Qaida members.

Late Sunday, U.S. officials said they were trying to ascertain whether one of the men, described as an Egyptian, is actually Saif al-Adel, Osama bin Laden’s security chief.

“We don’t know for sure,” said one U.S. official. “The guy’s not talking.”

Authorities said the seized items may ultimately prove to be a significant breakthrough in the war on terrorism, in that they could contain the names of al-Qaida members, details of past and present terrorist plots, and the locations of “sleeper” cells in the United States and overseas.

Mohammed, they noted, is considered to be the single most important al-Qaida leader — more so than Osama bin Laden — in terms of re-establishing the terror network and overseeing plots to launch attacks. He has been linked to most of al-Qaida’s most devastating terror attacks on four continents, dating to the bombing of the World Trade Center in 1993.

Attacks already planned?

But the good news about the trove of information was tempered by recent intelligence reports indicating that Mohammed had been coordinating and planning many attacks in the weeks before his arrest. Some of them appeared ready to be launched against targets in the United States, U.S. officials said.

“There were indications that he was involved in planning attacks (that were) not far away,” said one U.S. official, speaking on condition of anonymity. The official said authorities had identified “several in the United States and elsewhere,” based on credible intelligence.

“He was an active fellow,” the official said of Mohammed, a 37-year-old Kuwaiti born to Pakistani parents.

Khalid Shaikh Mohammed, the alleged Sept. 11 mastermind, shortly after his capture Saturday during a raid in Pakistan.

One U.S. intelligence memo dated Feb. 26 and reported Sunday by Newsweek’s Web site warned that Mohammed was overseeing an effort to have al-Qaida sleeper cells in the United States attack suspension bridges, gas stations and power plants in major cities, including New York, the official confirmed.

That information came from at least one captured al-Qaida soldier who knew Mohammed personally, and it was corroborated by other sources, the U.S. official confirmed in an interview. In some attacks, terrorists would ram tanker trucks into fuel pumps at gas stations, while other attackers would blow up suspension bridges or slash their cables, the official said.

“He indicated that Mohammed would go back to plots that he had previously worked on that had not yet come to fruition, and there was other information from other sources which pointed to the same kind of things that we were hearing from the detainees,” the official said.

Asked if U.S. counterterrorism authorities believed that the plotters were somewhere in the United States, the official said, “We don’t know.”

‘Could be the mother lode’

After authorities confirmed that Mohammed was indeed the man detained in the guest house of a Pakistani religious leader, they seized on the electronic gear and immediately began trying to extract information, officials said.

By Sunday, U.S. forensic experts had made limited progress in deciphering the jumble of data contained in the documents and computers. They reported that the data appeared to include “operational detail, names … including al-Qaida operatives around the world, including here” in the United States, one federal law enforcement official said.

“It could be the mother lode of information that leads to the inner workings of al-Qaida,” the law enforcement official said. “How they work, where they work, who they are, what their financial structure is.”

Time of the essence

But that official and others said they had a short window of opportunity — a few days at most — before potentially thousands of al-Qaida operatives would bore deep underground, disappear or, worse, try to launch attacks out of fear that Mohammed’s capture could lead to further arrests.

As a result, he said: “We are moving quickly on this. We are trying to pinpoint. So the next 48 hours, the next week, we may find ourselves locking some of these guys up.”

Officials at the National Security Agency also listened attentively to their vast global array of electronic eavesdropping satellites, waiting for an expected flurry of e-mails and cell phone calls among al-Qaida members. And authorities watched for the movement of cell members seeking cover, particularly those believed to be in direct contact with Mohammed.

Lawmakers overjoyed

Meanwhile, U.S. counterterrorism officials and lawmakers were jubilant Sunday in describing Mohammed’s arrest.

“This is a very huge event,” said Rep. Porter J. Goss, R-Fla., chairman of the House Intelligence Committee, in an appearance on ABC’s “This Week.”

Goss, like other intelligence officials, did not comment on specifics. But he did say that the arrest could be considered a success whether Mohammed cooperated or not.

“This is just extremely important, and it’s going to lead to other very successful activities very shortly, I’m sure,” Goss said.

Asked if Mohammed knew the whereabouts of bin Laden, Goss said: “Yes, I think he does know. And I suspect he has been in contact with him as well.”

Mohammed was being held Sunday under extremely heavy guard at an undisclosed location in U.S. military custody.

Brutal questioning

Several officials said that although they did not know the specific details, Mohammed was probably undergoing a brutal battery of round-the-clock interrogations, as well as forced sleep deprivation, psychological manipulation, exposure to bitter cold or intense heat, and perhaps even drugs in an effort to break his will.

Pakistani authorities detained Mohammed’s two young sons in a raid last September, and one official suggested that the boys could be used as some form of leverage. Others discounted that scenario, saying that someone who has boasted about being the orchestrator of attacks that killed thousands of people would be unlikely to waver for family reasons.

Vincent Cannistraro, former head of counterterrorism for the CIA, said late Sunday that the CIA was trying to determine whether the Egyptian captured with Mohammed is indeed Al-Adel, bin Laden’s security chief. But he said those efforts were hampered by a lack of current photos of the man. Pakistani officials have identified the Egyptian as an important al-Qaida figure, without commenting further.