The charges

Conspiracy to commit acts of terrorism transcending national boundaries Conspiracy to commit aircraft piracy Conspiracy to destroy aircraft Conspiracy to use weapons of mass destruction Conspiracy to murder US Government employees Conspiracy to destroy US Government property

He has been held in custody as a material witness in the investigation of the attacks.

Mr Moussaoui, a French citizen of Moroccan descent, is the first person to be indicted since the suicide attacks which killed an estimated 3,900 people.

Four of the six charges faced by Mr Moussaoui are punishable by death if he is found guilty, said US Attorney General John Ashcroft.

Brenda Keene, the admissions director at a flight school in Oklahoma where Mr Moussaoui trained, said he was polite though exasperating at times.

Al-Qaeda will now meet the justice it abhors

John Ashcroft

He was not regarded as a good student and was not allowed to fly solo even after 57 hours of instruction, compared with 12 to 20 hours for most students, she said.

His behaviour at the school - where he trained before moving to Minnesota - did not arouse suspicion, she added.

The indictment came as ceremonies commemorating the dead were held around the world exactly three months after the attack.

Conspiracy

More than 1,000 people have been arrested in the United States since the attacks - most of them have not been identified by the US authorities.

Mr Ashcroft said the 30-page indictment also named Mr Moussaoui's co-conspirators, including Osama Bin Laden, America's prime suspect in the terror attacks

"Al-Qaeda will now meet the justice it abhors," Mr Ashcroft said.

The attorney general said the indictment was "another victory in the war against terrorism."

The indictment brought by a grand jury in the eastern district of Virginia, says Mr Moussaoui underwent the "same preparation for murder as the hijackers".

Mr Moussaoui is alleged to have received training in al-Qaeda camps in Afghanistan, sought pilot training and to have received funding from sources in Germany and the Middle East.

Chemical attack fears

Mr Moussaoui has been the subject of intense scrutiny since the attacks, which occurred while he was in custody.

The FBI had wanted to examine the hard drive of his computer, but the Justice Department refused to grant a search warrant because there did not seem enough evidence to suggest he was a terrorist threat.

US officials had earlier mentioned Mr Moussaoui as a possible 20th member of the suicide hijacking team.

The FBI director said the computer showed that Mr Moussaoui had gathered information about the "dispersal of chemicals" as well as about crop-duster planes.

The discovery prompted the Bush administration to temporarily ground crop-dusters as a precaution against a possible biochemical attack.