Khalid Sheikh Mohammed to be tried at Guantánamo Bay

Khalid Sheikh Mohammed, the self-confessed mastermind of the September 11 attacks, will be tried by a military court at Guantánamo Bay rather than a civilian court, in a major policy reversal by the Barack Obama administration.

The Justice Department announced that plans had been dropped to transfer Sheikh Mohammed and four other accused conspirators to New York, after protests by local police and politicians about cost and security risks.

Jay Carney, the White House spokesman, said: "The president's primary concern is that the accused perpetrators of that terrible attack on the American people are brought to justice as fairly as possible and as swiftly as possible."

The move will disappoint the president's liberal supporters and human rights groups, who have condemned him for renewing the judicial terror policies of George W Bush.

It was however expected after the president announced last month that he was renewing military trials at Guantánamo following strong opposition in Congress to his plans to close the controversial prison for al-Qaeda suspects.

Sheikh Mohammed and his co-accused went on trial in a high-security court in Guantánamo in June 2008 but the already faltering proceedings ground to a halt when Mr Obama came to power six months later, vowing to usher in a new era that would uphold traditional models of justice.

The trial will inevitably raise questions about harsh interrogations used by CIA agents. Sheikh Mohammed was "waterboarded" or subjected to simulated drowning 183 times during his three years in secret US prisons.

Arrested in Rawalpindi, Pakistan in 2003, the US-trained engineer was transferred to Guantánamo in September 2006.

Once regarded as number three in Osama bin Laden's al-Qaeda hierarchy, he claims to have personally beheaded American journalist Daniel Pearl in 2002 with his "blessed right hand" and to have helped in the 1993 World Trade Center bombing that killed six people.

In reported confessions released by US authorities, Sheikh Mohammed was quoted as claiming to be "military operational commander" for all al-Qaeda foreign operations.

There are currently 172 prisoners remaining in Guantánamo, but only 40 have been earmarked for trial. The Obama administration has admitted that under a new legal code many of the rest will be held indefinitely without trial.