A Guantanamo Bay detainee accused of links to al-Qaeda will face a military commission after an appeal court overturned a judge's ruling.
Canadian Omar Khadr was accused of killing a US soldier in 2002
A US military appeals court ruled that Omar Khadr, a Canadian citizen, is an "unlawful enemy combatant" and can be tried on terror charges.
The ruling reverses an earlier one by a military judge, who dismissed the charges on a technicality in June.
Mr Khadr was only 15 when he was captured in Afghanistan five years ago.
Under a new system of military justice approved by the US Congress last year, detainees facing trial must be designated "unlawful enemy combatants".
But when they were assessed on entering Guantanamo Bay they were officially described only as "enemy combatants".
The absence of the word "unlawful" meant that detainee would have to be treated as a prisoner of war and be protected by international law.
It gave the new military tribunals no jurisdiction, according to the military judges who heard Mr Khadr's case.
Now, in its first ruling, the Court of Military Commission Review, the body created to hear appeals arising from this issue, has ruled that a military court set up by the US government is the right venue in which to try Mr Khadr.
Critics have questioned the legality of the military appeal court, which was quickly set up and staffed after the Bush administration appealed against the judge's ruling.
But the BBC's Rajesh Mirchandani, in Washington, says the ruling represents a victory for the Bush administration in a long battle over how to prosecute the detainees.
Mr Khadr, now 20, is accused of killing a US soldier during a battle at a suspected al-Qaeda base in 2002.