Moussaoui's courtroom testimony has often been contradictory

The prosecution had called for the death sentence, arguing that "there is no place on this good Earth" for him.

But defence lawyers successfully argued he should face life in prison, rather than martyrdom through execution.

As the verdict was read out, Moussaoui, the only man to be prosecuted over 9/11, shouted: "America, you lost!"

During six weeks of testimony in a Virginia court, prosecutors had argued he withheld information that could have helped prevent the attacks on New York and Washington.

Under cross-examination, Moussaoui said he had "no regret, no remorse" and wished it could be 11 September 2001 every day.

'Minor role'

Moussaoui was arrested on immigration charges at a flight simulator school in Minnesota in August 2001.

The greater value I think would have been if he was executed Rudolph Giuliani Former Mayor of New York Final act for a 9/11 extra 9/11 families react

Although he was in jail at the time of the attacks, prosecutors said he told lies to allow the plot to continue.

Although full details of the jury's vote have not been made public, a court spokesman said the verdict in favour of life imprisonment was not unanimous.

But Moussaoui received the sentence nonetheless because under US law, all members of a jury must be in agreement where a death sentence is to be handed down.

Jurors did unanimously reject the suggestion - put forward by Moussaoui's defence - that the death penalty would help fulfil the defendant's visions of martyrdom.

The right decision. To execute him would be to condone state sanctioned murder and only play into the hands of fanatics Michael Los Angeles Your views: Moussaoui ruling

Three jurors felt his knowledge of the 9/11 plot was limited and three jurors said that if he was involved in the attacks, his role was a minor one.

According to BBC correspondent Matt Frei, the government effectively lost the case.

He says the prosecution failed to demonstrate to jurors that Moussaoui had known the whole truth about the attacks beforehand - and that had he told the truth, the attacks would have been prevented.

'America won tonight'

During the six-week sentencing trial, the jury of nine men and three women sat through tortuous legal arguments and harrowing evidence gathered from the bloodiest terror attacks in US history.

Testimony was heard from witnesses who survived the attacks on New York and Washington and pictures were shown of the carnage caused when the hijacked aircraft crashed into their targets.

Jury verdict in full (1.2 MB) Most computers will open PDF documents automatically, but you may need to download Adobe Acrobat Reader. Download the reader here

The jury also heard a voice recording from the cockpit of the hijacked United Airlines flight that crashed into a field in Pennsylvania.

Carrie Lemack, whose mother died aboard one of the aircraft hijacked on 9/11, said after the verdict that Moussaoui had got the sentence he deserved.

"He was an al-Qaeda wannabe. He wanted to kill Americans," she said.

The verdict clearly upset one of the jurors, according to BBC correspondent James Coomarasamy.

Many of the victims' families were not happy with the verdict - though others said they were relieved Moussaoui had not been allowed to become a martyr.

The former Mayor of New York, Rudolph Giuliani, who was in the city at the time of the attacks and testified in Moussaoui's trial, said a death sentence ought to have been passed on a man who lied to investigators about the plot.

"If he'd told the truth he could have prevented it. For me, that would make him a material and very important part of the conspiracy," Mr Giuliani said.

But, he added, the verdict had reinforced his faith in the US justice system.

"The greater value is demonstrating what America is like, he said. "America won tonight."

US President George W Bush said the verdict presented "the end of this case but not an end to the fight against terror".