At the time of his arrest Saturday, a senior al Qaeda leader defiantly told his captors that "only the American infidels will celebrate this" and went on to predict a spate of terrorist attacks on U.S. forces massing in the Persian Gulf region for a likely invasion of Iraq, Pakistani intelligence officials said today.

Khalid Sheik Mohammed, who is accused of masterminding the Sept. 11, 2001, terrorist attacks on New York and the Pentagon, was described as unrepentant and almost cocky during his initial interrogation Saturday by agents from Pakistan's Inter-Services Intelligence agency.

According to a Pakistani official who was at the interrogation, Mohammed lectured his captors on their proper role as Muslims, telling them, "Playing as American surrogate won't help you or your country."

Mohammed also told the Pakistani agents that "there are dozens of people like me who will give their lives but won't let the Americans live in peace anywhere in the world," the official said.

Mohammed, seemingly relaxed, spent several hours talking with the Pakistani interrogators at a military facility in Rawalpindi, the city where he was captured, before he was handed over to U.S. officials and flown out of the country Saturday night, officials said.

Several times during the interrogation, the intelligence official said, Mohammed said his arrest would not limit the potential of his comrades to strike U.S. interests.

"Let the Iraq war begin -- the U.S. forces will be targeted inside their bases in the gulf," the official quoted Mohammed as saying. "I don't have any specific information, but my sixth sense is telling me that you will get the news from Saudi Arabia, Qatar and Kuwait."

Mohammed, 37, is thought to be the third-ranking figure in al Qaeda, behind Osama bin Laden and Ayman Zawahiri, both of whom are still at large. His arrest has raised hopes among U.S. officials of a breakthrough in the hunt for bin Laden, although Mohammed's initial interrogation yielded no specific information on the whereabouts of the Saudi-born fugitive, according to the official who was present and another intelligence official.

The official who witnessed the interrogation said that when Mohammed was asked whether bin Laden was alive, he replied, "Of course he's alive." Both officials said, however, that at no point during his interrogation did Mohammed mention meeting bin Laden after Sept. 11, 2001, and they denied news reports that evidence seized in the raid Saturday -- including documents, a computer and computer disks -- indicated recent communication between the two.

"There were no documents recovered from Mohammed that may prove his meetings with Osama," one of the officials said. "Do you expect the world's top-most terrorists to document their meetings?"

Besides dealing a blow to al Qaeda, Mohammed's arrest may also have severed a key link between the organization and Pakistani militant groups, including those responsible for the murder last year of a Wall Street Journal reporter, Daniel Pearl, according to Pakistani security officials and analysts.

Based on information that developed during the hunt for Mohammed, who was nearly caught at least three times over the past five months, it now appears that he was a principal liaison between al Qaeda and Lashkar-i-Jhangvi, a Pakistani Islamic militant group blamed for scores of sectarian killings, as well for attacks on Christians and Westerners over the last year, security officials said.

The connection between al Qaeda and Lashkar-i-Jhangvi is significant because it reinforces what U.S. and Pakistani intelligence services have long suspected: that after fleeing U.S. forces in Afghanistan last year, surviving members of al Qaeda, most of them Arabs, not only took refuge with Pakistani extremists but also made common cause with them in plotting attacks on Western interests in Pakistan.

Pakistani police officials have accused Lashkar-i-Jhangvi and another Pakistani militant group, Jaish-i-Muhammad, of joining forces in the kidnapping and murder of Pearl, and some officials now believe that a key figure in the plot -- a Lashkar member named Naeem Bukhari -- may have been taking orders directly from Mohammed.

"The profile of the Pearl case mastermind resembles Khalid's personality and style so much," said a Pakistani police official involved in the Pearl investigation. "He should have direct knowledge about this case."

Mohammed, who attended college in the United States, would have been exceptionally well qualified to coordinate the efforts of al Qaeda and Pakistani extremists. A Kuwaiti born to Pakistani parents, he speaks fluent Urdu and Baluchi -- two of the main languages in Pakistan -- and could easily pass as a Pakistani, officials said.

"For us Mohammed was an important bridge between militant Pakistanis and militant Islamic cadres, particularly Lashkar-i-Jhangvi and al Qaeda," a Pakistani official said.

Besides the Pearl murder, officials suspect that al Qaeda may have played a role in several high-profile terrorist attacks over the last year, including car bombings in Karachi -- one of them aimed at the U.S. Consulate -- assaults on churches and a mission school, and the killing by a Pakistani gunman of two policemen in a second attack on the consulate last week.

In a related development, Pakistani officials said they were exploring the possibility of a link between al Qaeda and elements within the country's largest Islamic political party, Jamaat-e-Islami.

Party activists have been accused of harboring al Qaeda fugitives including Mohammed, who was asleep at a home owned by a party organizer in Rawalpindi when he and another senior al Qaeda figure, Mustafa Ahmed Hawsawi, were apprehended Saturday.

Pakistani officials and analysts expressed hope that the capture of the two men would deal a blow to the ability of al Qaeda and local militants to coordinate future attacks.

"I would say it's a turning point," said Mushahid Hussain, a former information minister and academic who now writes a syndicated newspaper column here. "If there was any center of gravity for Lashkar-i-Jhangvi, for al Qaeda and Taliban remnants, it's this guy. He was the link. All paths led to this chap, so I think the back has been broken."

Lancaster reported from Islamabad.