The U.S. must hold court hearings to determine whether suspected terrorists imprisoned at Guantanamo Bay are prisoners of war or unlawful enemy combatants, a military judge said in a ruling that could delay war crimes trials.

The judge, Navy Capt. Keith Allred, said in a ruling issued late Monday in Washington that a military administrative panel's status finding is not enough by itself to proceed with a trial at the U.S. base.

Only unlawful enemy combatants can be tried before the military tribunals under a 2006 law that set up the war crimes trials.

Defense lawyers praised Allred's ruling, which would give detainees another opportunity to prove they are beyond the jurisdiction of the tribunals.

But a spokesman for the Office of Military Commissions, Army Maj. Robert Gifford, said the effect of the ruling is limited because it is not binding on other judges. Military prosecutors have not decided whether to appeal, he said.

Allred made the ruling in the case of Salim Ahmed Hamdan, a former driver for Osama bin Laden charged with conspiracy and supporting terrorism. The judge held two days of hearings this month on whether the Yemeni is an unlawful enemy combatant or a prisoner of war.

The judge said those two days of hearings would serve as a court hearing on his prisoner-of-war status and is expected to issue a ruling soon.

The U.S. holds about 290 men at Guantanamo on suspicion of terrorism or links to al-Qaida or the Taliban and has said it plans to prosecute about 80 before the military tribunals. It has charged three so far and obtained one conviction through a plea bargain.