Canadian Omar Khadr's case may be the first to be brought before a U.S. appeal body that will review the legalities of his detention in Guantanamo Bay The Globe and Mail reported Monday.
Last month, charges against Khadr, 20, were dismissed by a military commission judge because he was not identified as an "unlawful" enemy combatant.
On Friday, a military judge refused a request from the Pentagon to reinstate the charges against Khadr.
Navy Commander Jeffrey Gordon said Saturday the military is preparing to challenge the decision by the new appeal body.
"We're disappointed with the judge's decision in this matter,'' Gordon said.
The Court of Military Commissions Review was set up within a week of the dismissal of the two detainees' charges on June 4.
There are no plans to release Khadr from the U.S. detention centre, but his lawyers and several human rights groups are urging the Canadian government to put pressure on Washington.
Khadr was one of only three people at Guantanamo Bay in Cuba to be charged.
He was classified as an "enemy combatant" by a military panel in 2004. But because he was not classified as an "alien unlawful enemy combatant," the judge was forced to dismiss the charges against him.
None of the detainees held at the prison have been deemed "unlawful."
The son of an alleged al Qaeda financier, Khadr was accused of killing U.S. Army Sgt. Christopher Speer with a grenade during a firefight in Afghanistan on July 27, 2002.
Khadr became the first juvenile to be charged with war crimes in modern history.
With files from the Associated Press