Hours after being sworn in as US President, Barack Obama has called for a halt to Guantanamo war crimes tribunals, a move which will begin the long awaited process of dismantling the prison itself.
His request for a 120-day suspension of all 21 pending tribunals will bring to a halt the case against Khalid Sheikh Mohammed, the self-proclaimed 9/11 mastermind and four co-defendants who faced the death penalty if convicted.
Military judges are expected to rule on Mr Obama's request to halt the trials today at the US naval base.
The request by Mr Obama was widely anticipated - he had already vowed to close down the prison and its controversial military commission trial system.
"In order to permit the newly inaugurated president and his administration time to review the military commission process, generally, and the cases currently pending before the military commissions, specifically, the secretary of defense has, by order of the president directed the chief prosecutor to seek continuances of 120 days in all pending case," prosecutor Clay Trivett said, in the written request to the judges.
The request said that freezing the trials until May 20 would give the new administration time to evaluate the cases and decide what forum best suits any future prosecution.
About 245 foreign captives are still held at the detention centre that opened in January 2002. The Bush administration had said it planned to try 80 prisoners on war crimes charges, but only three cases have been completed.
Defence lawyers had complained that the tribunals allowed hearsay evidence and coerced testimony, and were the subject of so much political interference that fairness was impossible.