US military judges have dropped all war crimes charges against the only two Guantanamo captives facing trial.
A demonstrator, disguised as Guantanamo prisoner protests against torture at the G8 Summit in Germany today
The judges said they lacked jurisdiction under the strict definition of those eligible for trial by military tribunal under a law the US Congress passed last year. The ruling could prevent the trial of any of the 380 prisoners held at the US base in Cuba soon.
"It's another demonstration that the system simply doesn't work," said the tribunals' chief defence counsel, Col Dwight Sullivan.
The rulings do not affect US authority to indefinitely hold the 380 foreign terrorism suspects detained at the Guantanamo Bay naval base in southeast Cuba.
But it was the latest setback for the Bush administration's efforts to put the Guantanamo captives through some form of judicial process. It was forced to rewrite the rules last year after the US Supreme Court deemed the old tribunals illegal.
Charges were dropped for Omar Khadr, a Canadian captured in a firefight in Afghanistan at age 15. Khadr (20) was accused of killing a US soldier with a grenade and wounding another in a battle at a suspected al-Qaeda compound in Afghanistan in 2002.
Charges were also dropped for Salim Ahmed Hamdan of Yemen, who is accused of driving and guarding Osama bin Laden. Hamdan last year won a US Supreme Court challenge that scrapped the first Guantanamo tribunal system.
Both had been charged with conspiracy and providing material support for terrorism. Khadr also faced charges of murder, attempted murder and spying.
Both defendants had been declared "enemy combatants" during administrative hearings that started at Guantanamo in 2004 to determine if there were grounds to continue holding them.
But the judge for Hamdan's case said that definition was broad enough to include captives who supported the Taliban or al-Qaeda without actually engaging in combat.
He said the Military Commissions Act adopted by the US Congress in 2006 set more stringent rules and allowed only those designated as "unlawful enemy combatants" to face trial in the Guantanamo tribunals.
No Guantanamo captives have been formally designated as "unlawful enemy combatants," and defence lawyers said none could be tried unless they first faced proceedings reclassifying them as such.
Four prisoners have committed suicide at Guantanamo since the detention and interrogation camp opened in 2002.