Canadian citizen Omar Khadr, a former Guantanamo Bay inmate now serving time in Edmonton Institution, will remain in the federal penitentiary after an Alberta judge rejected arguments that he be transferred to a provincial jail.

The decision Friday comes after a hearing last month, when Khadr's lawyer, Dennis Edney, argued before Associate Chief Justice John Rooke that Khadr was only 15 years old when he killed an American soldier in Afghanistan, so the now-27-year-old should be in a provincial jail.

Edney disagreed with the ruling, saying he will appeal to a higher court.

Rooke "made a mistake in fact and in law … in his interpretation of Section 20 of the International Transfer of Offenders Act," said Edney.

Rooke said his decision is based solely on his interpretation the Act.

"This decision, simply and purely, is … about the proper interpretation of legislation to determine whether an offender, transferred from another country to Canada, will serve the remainder of the foreign sentence in a provincial correctional facility for adults or a federal penitentiary.

"It is not about whether it would be better or worse for Mr. Khadr to serve his sentence in a provincial or federal institution," he wrote in his ruling.

Edney maintains if Khadr's crime had occurred in Canada, his eight-year sentence would have fallen under what was then called the Young Offenders Act (now the Youth Criminal Justice Act), placing him in a provincial facility.

The federal government opposed the application, arguing Khadr is appropriately placed in an adult maximum-security facility, because though he was sentenced as a youth on the murder conviction, he was sentenced as an adult on four other convictions.

In 2002, Khadr, who was born in Toronto, was taken into custody for the death of an American soldier. Khadr was discovered in the rubble of a bombed-out compound in Afghanistan after a firefight with U.S. forces.

He pleaded guilty to five charges, including the murder of Sgt. 1st Class Christopher Speer and providing material support for terrorism, in exchange for returning to Canada to serve his sentence.

He was returned to Canada in September 2012 and incarcerated in Millhaven Institution near Kingston, Ont., before he was moved last May to Edmonton Institution where he was kept in segregation.

As long as he remains in a maximum institution, Khadr has no chance at parole, Edney maintains.