At least one hijacker on each of the four planes in Tuesday's terrorist attacks was trained at a US flight school, the US Justice Department says. Overall, 50 people may have been involved in the hijackers' well-financed operation.
The FBI's massive investigation stretches from the Canadian border to Florida, where some of the participants learned how to fly commercial planes before the attacks. Justice Department spokeswoman Mindy Tucker said Wednesday that schools in more than one state were involved in the training of the hijackers, several of whom had pilots' licenses.
Multiple cells of terrorist groups participated in the operation and the hijackers had possible ties to countries that included Saudi Arabia and Egypt, said law enforcement officials, speaking on condition of anonymity.
Officials said authorities were gathering evidence that the terrorist cells may have had prior involvement in earlier plots against the US, and may have been involved with Saudi exile Osama bin Laden. That includes the USS Cole bombing in Yemen and the foiled attack on US soil during the millennium celebrations.
The identities of more than a dozen of the men who hijacked the four planes with knives and threats of bombs has been ascertained, the officials said.
For some suspected accomplices, "we have information as to involvement with individual terrorist groups," FBI Director Robert Mueller said.
Attorney General John Ashcroft said 12 to 24 hijackers commandeered the four planes, and a government official said another two dozen or so are believed to have assisted them. About 40 of the men have been accounted for, including those killed in the suicide attacks, but 10 remain at large, the Los Angeles Times reported Wednesday night on its Web site, citing an unidentified source with knowledge of the investigation.
The Times reported at least one of the suspects receiving advanced flight training in Florida was a commercial pilot from Saudi Arabia. At least one hijacker on each of the four planes was trained at a US flight school, Tucker said. The Times said authorities believe 27 suspected terrorists received pilot training.
Authorities detained at least a half dozen people in Massachu-setts and Florida on unrelated local warrants and immigration charges and were questioning them about their possible ties to the hijackers.
Search warrants were executed in Florida, New Jersey and Massachusetts. Sealed warrants went out in several other states, officials said.
Dramatic transcripts and reports of hurried cell phone conversations suggest that some passengers aboard doomed United Airlines Flight 93 may have struggled with the hijackers, thwarting an attempt to crash into another target.
At least two passengers apparently used cellular telephones to report plans to try to attack the men who took over the aircraft.
Crowded into the back of the plane, the remaining passengers somehow became aware after 9am that two other flights hijacked out of Boston had struck the World Trade Center towers.
Jeremy Glick, a 31-year-old passenger, called his wife in New Jersey and told her that men on the plane had decided to resist the hijackers. Glick told his wife that three Middle Eastern men wearing red headbands, with knives and a box they claimed to be a bomb, had taken over the cockpit.