"I am referring the cases of Khalid Sheikh Mohammed, Whalid Mohammed bin Attash, Ramzi bin al-Shibh, Ali Abdul Aziz Ali, and Mustafa Ahmed al-Hawsawi to the Department of Defence to proceed in military commissions," US Attorney General Eric Holder said at a news conference.

This is a complete reversal of his November 2009 announcement that Sheikh Muhammad and four other individuals would stand trial in federal court for their roles in the terrorist attacks on the US on September 11, 2001.

"I stand by that decision today," Holder said but quickly added that he has reversed his previous decision because of the opposition from Congressmen who intervened and imposed restrictions blocking the administration from bringing any Guantanamo detainees to trial in the US.

"Sadly, this case has been marked by needless controversy since beginning. Despite all arguments and debate it has engendered, the prosecution of Khalid Sheikh Mohammed and his co-conspirators should never have been about settling ideological arguments or scoring political points," he said.

Known as "KSM," Sheikh Mohammed is the self-proclaimed architect of the 9/11 attacks and a host of other plots.

Sheikh Mohammed was arrested in 2003 in Rawalpindi in Pakistan and handed over to American agents who held him in secret prisons for over three years before sending him to Guantanamo in September 2006.