Hijackers were trained at US flight schools

At least one hijacker on each of the four planes in Tuesday's terrorist attacks was trained at a US flight school, the Justice Department said. Overall, 50 people may have been involved in the hijackers' well–financed operation.

"Both cash and credit cards were used" by the hijackers "to purchase tickets, hotel rooms and other things," Justice Department spokeswoman Mindy Tucker said today.

The Federal Bureau of Investigation's huge investigation stretches from the Canadian border to Florida, where some of the participants learned how to fly commercial planes before the attacks. She said flight schools in more than one state were involved in the training of the hijackers, several of whom had pilots' licences.

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.

Officials said authorities were gathering evidence that the terrorist cells may have had prior involvement in earlier plots against the United States, 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 are known, 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. At least one of the suspects receiving advanced flight training in Florida was a commercial pilot from Saudi Arabia.

Mr Ashcroft said the investigation was complicated by "the destruction of those who perpetrated the crime and much of the evidence being destroyed."

About 40 of the people involved in the attacks 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.

Some of those involved in the plot left suicide notes, but they are not believed to have been the hijackers, a government source told The Associated Press. It's unclear whether those who left the notes actually killed themselves.

Authorities detained at least a half dozen people in Massachusetts 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.

A Venice, Florida, man said FBI agents told him that two men who stayed in his home while training at a local flight school were involved in the attacks. Charlie Voss, a former employee at Huffman Aviation in Venice said the FBI told him one of men was named Mohamed Atta. A student at Huffman Aviation identified the second man as Marwan Alshehhi.

Citing federal authorities, The Miami Herald reported today that Atta was one of four suspects who died on American Airlines Flight 11, the first jetliner to crash into the World Trade Centre.

"This could have been the result of several terrorist kingpins working together. We're investigating that possibility," one law enforcement official speaking on condition of anonymity told The Associated Press.

Sen. Charles Grassley of Iowa, the top Republican on the Senate Finance Committee, said the briefing he received on Wednesday from law enforcement left him with the same impression.

"Most of it today points to Osama bin Laden, but the speculation at the end of the road is that he and his network were very much involved with Hezbollah, Fatah and other" terrorist organizations, Grassley said.

The senator said authorities told him all the hijackers were of Middle Eastern descent and that they had "a tremendous amount of ground support for each hijacker."

Ashcroft said numerous promising leads were being followed up. "The Department of Justice has undertaken perhaps the most massive and intensive investigation ever conducted in this country," he said.