FBI and CIA officials were advised in August that as many as 200 terrorists were slipping into this country and planning "a major assault on the United States," a high-ranking law enforcement official said Wednesday.
The advisory was passed on by the Mossad, Israel's intelligence agency. It cautioned that it had picked up indications of a "large-scale target" in the United States and that Americans would be "very vulnerable," the official said.
It is not known whether U.S. authorities thought the warning to be credible, or whether it contained enough details to allow counter-terrorism teams to come up with a response. But the official said the advisory linked the information "back to Afghanistan and [exiled Saudi militant] Osama bin Laden."
"There was a connection there," he said.
Separately, federal authorities are gathering evidence that suggests that a small network of individuals helped fund and protect some of the 19 suicide attackers by providing cash, documents and possibly even safe houses.
Atty. Gen. John Ashcroft has said that authorities suspect that more airplanes were going to be hijacked and that other co-conspirators, possibly handlers and associates of the suicide attackers, remain at large.
Mindy Tucker, spokeswoman for the Justice Department, said Wednesday that "we believe there are associates of the hijackers that have connections to the terrorist network that are present in the United States."
Other law enforcement authorities said such logistical support is typical within many terrorist cells.
Some participants help others slip unnoticed from city to city, and country to country, by providing them with fake or fraudulent passports, cash gained through bank and credit-card fraud, and havens in their homes or in apartments rented under aliases, the authorities said.
Officials continue to scrutinize the backgrounds of several individuals now in detention. They include Habib Zacarias Moussaoui, who was in a Minnesota jail on an Immigration and Naturalization Service violation on the morning that the World Trade Center towers were destroyed. He is now being questioned in connection with the attacks.
Moussaoui's parents were born in Morocco, and he is a French citizen, born in the southern town of St. Jean de Luz in May 1968, according to an official at the French Embassy in London. It was reported earlier that he was a French Algerian.
According to news reports, Moussaoui earned vocational degrees in automotive mechanics. On his university application, he expressed particular interest in learning business English so he could travel and "work in an international business."
French officials confirmed that Moussaoui was on a special immigration watch list because of his suspected ties to Islamic terrorists and because he had made several trips to Afghanistan.
Moussaoui spent at least three years in Britain in the late 1990s, according to French officials. He came to the French Embassy in London in September 2000 and had his French passport extended. At the time, he described himself as unemployed and said he had lived at several addresses in the suburbs of London.
By this year, however, he was able to afford to travel to the United States and begin flying lessons. He was arrested Aug. 17 after the staff at a flight school grew concerned about his offer of thousands of dollars in cash for instruction in how to fly jumbo jets and his lack of interest in learning to take off or land jets.
Authorities also continue to question two men removed from a train in Fort Worth on the day of the attacks. They had a large sum of money with them--$20,000 in cash--as well as box cutters similar to those allegedly used by the hijackers on at least one of the commandeered planes, one source said.
The men had boarded a flight in Newark, N.J., that was bound for San Antonio on the morning of the attacks. But the flight was diverted to St. Louis after the World Trade Center was hit, and the two men then took an Amtrak train to Texas.
The train was stopped in Fort Worth on a routine check for drugs, and the men were detained because of the materials and cash they were carrying. The train's final destination was San Antonio.
Also Wednesday, owners of fitness clubs in Florida and Maryland said several of the suspected hijackers had worked out in their gyms.
"They may have been told to go get as strong as they could get in case of body conflict or a fight," said Jim Woolard, who owns eight World Gyms in Florida's Palm Beach and Broward counties.
Ziad Jarrahi, a suspected hijacker on the plane that crashed in Pennsylvania, made no secret of his aim: to learn how to fight.
On May 6, he signed up for a two-month membership, later extended to four, at the U.S. 1 Fitness Center in Dania Beach, north of Miami.
"He told me that he was from Germany, that he was visiting," said Roxanne Caputo, who is in charge of sales. "He would come in every day, sometimes twice."
Jarrahi took classes in various combat techniques, including full-contact boxing, kick-boxing and the Brazilian martial art of Kopthaikido, Caputo said. He made two cash payments of $500 each to owner Burt Rodriguez to get some private one-on-one instruction.
Rodriguez recalled that his former pupil was soft-spoken, physically fit and a diligent learner but that he lacked the "spark" of a born combatant.
"I've seen a lot of guys with the gloves on, and he was the kind who just wanted to survive," he said.
During 17 lessons with the Cuban-born instructor (Jarrahi missed the three final sessions for which he had paid), he was taught how to grapple, defend himself in close quarters and protect himself from somebody wielding a knife or stick.
A hijacker could have used those same skills to overwhelm a flight crew or fight with airline passengers, his former teacher acknowledged with regret.
"To defend yourself, you obviously learn how to attack, which is the other side of the equation," Rodriguez said. "If he wasn't one of the pilots, he would have done quite well in thwarting the passengers from attacking."
In the summer, five suspected hijackers on the two planes that crashed into the World Trade Center--Mohamed Atta, Marwan Al-Shehhi, Wail M. Alshehri, Waleed M. Alshehri and Satam Al Suqami--purchased one-month memberships at Woolard's gyms. Atta and Al-Shehhi paid to work out at the Delray Beach gym; the others in Boynton Beach.
"They may have been doing it for social reasons, or to get strong for the upcoming battles," Woolard said of the men.
Five men identified as the hijackers of the plane that slammed into the Pentagon also worked out in the week before the attacks. While living in a rundown motel on the outskirts of suburban Laurel, Md., they showed up in various groupings every day from Sept. 2-6 at a nearby Gold's Gym. Three of them--Khalid Al-Midhar, Majed Moqed and Hani Hanjour-- paid $30 in cash for a weeklong membership, while two others--Salem Alhamzi and Nawaq Alhamzi--paid $10 for each visit.
They spent their time training with weights and resistance machines, said Gene LaMotta, president and chief executive of Gold's Gym. The fitness counselor said the men had "wads" of cash. And when the counselor asked if they could translate their Arabic names into English, Hanjour said his first name meant "warrior."
In another development Wednesday, it was learned that U.S. authorities are looking into possible links between the hijackers and three Afghans arrested in the Cayman Islands.
Two weeks before the hijackings, an anonymous letter sent to a Cayman Islands radio station warned that the three might be involved with Bin Laden in preparing "a major terrorist act against the U.S. via an airline or airlines."
The day after the attacks, U.S. officials arrived in the Caymans to pick up evidence gathered by Cayman and British investigators in their yearlong probe of the men.
The men, who have identified themselves as Nez Nazar Nezary, Mohammad Raza Hussani and Ali Sha Yusufi, are in protective custody in the Caymans' Northward Prison. They said they boarded a ship in Turkey bound for Canada and were put ashore in a small boat in the Caymans, believing they had arrived in Canada.
But David Thursfield, police commissioner in the Caymans, said authorities are certain the men actually entered the Caymans from Cuba with Pakistani passports.
"You may have some bizarre things where you are, but this takes the biscuit here," Thursfield said.
Serrano reported from Washington and Dahlburg from Florida. Also contributing to this story were Times staff writers Ken Ellingwood, Robert L. Jackson, Myron Levin, Josh Meyer, Judy Pasternak and Sebastian Rotella, and researcher Nona Yates.