Washington ? The suspected mastermind of the cataclysmic Sept. 11 terror attacks and a decade-long list of other sinister acts was arrested Saturday in Pakistan, officials said.

Government officials and private security analysts called it the most significant arrest thus far in the war against terrorism.

Khalid Shaikh Mohammed, described as Osama bin Laden’s field general, was seized with two other terrorist suspects by FBI, CIA and Pakistani agents in a hideout in Rawalpindi, near the capital of Islamabad, authorities said.

A senior U.S. intelligence official said Mohammed was believed to have knowledge of pending terrorist attacks on the United States. When arrested, he carried names and telephone numbers of members of al-Qaida sleeper cells in North America, said the official, who requested anonymity.

Told that Mohammed was in custody, President Bush exclaimed: “That’s fantastic,” according to the White House.

Only bin Laden and his chief deputy, Ayman al Zawahri, rank higher on U.S. wanted lists. Mohammed’s ties to terrorists began in 1993, if not earlier, authorities said, making him responsible for a decade of terror against Americans at home and abroad.

Among the other attacks linked to Mohammed:

l The first bombing of the World Trade Center in 1993.

l A 1995 plot to blow up 12 U.S.-bound airliners over the Pacific Ocean.

l The 1998 suicide assaults on U.S. embassies in Africa.

l The 2000 attack on the USS Cole in Yemen.

l The April 2002 bombing of a synagogue in Tunisia.

U.S. officials suspect that one of the other men arrested Saturday is Saif al Adel, a high-ranking member of al-Qaida also allegedly linked to the deadly blasts at the U.S. embassies in Tanzania and Kenya in August 1998.

The whereabouts of Mohammed, the man who might be al Adel and a Pakistani man identified as Abdul Qadoos were unknown late Saturday. Reports from Pakistan suggested Mohammed was being taken to another location outside the United States.

American-educated

A Kuwaiti of Pakistani descent, Mohammed, 37, was partially educated at a Baptist college in North Carolina, had a reputation as a ladies’ man and blended easily into the Western society he professed to despise.

U.S. authorities have called him “The Forrest Gump of al-Qaida,” the one name that turns up whenever they examine the group’s terror plans.

Authorities also described him as a master of disguise and one of the most dangerous men on Earth. They put a $25 million bounty on his head and another $25 million on al Adel.

Both were on the FBI’s list of most-wanted terrorists.

Vincent Cannistraro, a former counter terrorism chief for the CIA, called the arrests “very significant” and said he expected that Mohammed would be interrogated “with some urgency” about al-Qaida attacks that might be imminent.

“Over the last 10 years, his fingerprints have been on most of al-Qaida’s operations,” Cannistraro said. “This is the capture of someone directly responsible for Sept. 11. It’s very important.”

The Bush administration holds Mohammed largely responsible for the deaths of more than 3,000 people in the Sept. 11, 2001, suicide attacks that toppled the World Trade Center in New York City, wrecked a wing of the Pentagon and destroyed four commercial jetliners.

They believe he convinced bin Laden that the plot could be planned and executed. A day before the attacks, Mohammed spoke with terrorist commander Mohammed Atta in a telephone conversation monitored by the National Security Agency but belatedly translated from Arabic into English.

“I never thought bin Laden was the brains behind this operation,” said Melvin Goodman, a former senior CIA analyst. “The masterminds and the real villains were the men below him, and now we have one of them.”

Ringside seat for terror

Mohammed has been present for many of al-Qaida’s most notorious plots. His nephew, Ramzi Yousef, was arrested in the Philippines for conspiring to blow up 12 U.S.-bound airliners in 1995, a plot Mohammed is believed to have led. Yousef was later convicted for the February 1993 World Trade Center bombing, which killed six and injured about 1,000.

The August 1998 suicide attacks on the U.S. embassies killed 12 Americans and 212 other people. More than 4,500 people were injured.

The man who drove the explosive-laden truck into the Tunisian synagogue phoned Mohammed three hours before the attack, according to Klaus Ulrich Kersten, Germany’s top police official. Twenty-one people died in the attack.

“He is probably the only man who knows all the pieces of the puzzle,” said French terrorism expert Roland Jacquard.

Jacquard said judicial documents in France show that Mohammed had more meetings with bin Laden than anyone else after al-Qaida’s leader moved from Sudan to Afghanistan.

In recent months, authorities believe, Mohammed actively recruited terrorists for a new wave of attacks against Americans at home and abroad. He is alleged to have worked to develop radioactive “dirty” bombs, Western intelligence officials said.

Mohammed traveled the world under a series of aliases and proved able to elude authorities for years. He gave Western intelligence officials the slip on a half-dozen occasions, narrowly escaping capture last September in Pakistan.

He had particularly strong ties to Kuwait and Qatar, two of the main staging areas for U.S. forces mustering for a possible invasion of Iraq. He is also alleged to have extensive connections in the Philippines and elsewhere in Southeast Asia.

Weakness for women

Mohammed passed easily in both Arab and Western worlds, speaking flawless English he picked up at Chowan College, a Baptist school in eastern North Carolina, and at North Carolina Agricultural and Technical State University in Greensboro, where he earned an engineering degree in 1986.

He is also said to be a charmer with a weakness for women and a flamboyant style. He preferred five-star hotels. He entertained in karaoke bars and mirrored go-go clubs.

While living in the Philippines, he once sought to impress a woman by chartering a helicopter and waving at her while chatting by cell phone.

He was known in the Philippines as Abdul Majid, a Saudi businessman. He lived on the top floor of Manila’s Jousefa Apartments with his nephew, Ramzi Yousef.

Mohammed also went by the names Salim Ali, Ashrai Refaat, Nabith Renin Khalid Abdul Waddod and Fahd Bin Abdullah Bin Khalid, among many others.

And now, he is in custody,

Michael Swetnam, a terrorism expert and former CIA analyst, called it “a milestone in the war on terrorism.”

“It’s very significant,” Swetnam said, “to find him and take him off the street.”