Omar Khadr, 22, has been imprisoned in the U.S. military prison in Guantanamo Bay, Cuba, since October 2002. He is alleged to have thrown a grenade that caused the death of a U.S. soldier. (CP)

The federal government will go to the Supreme Court in a bid to overturn court rulings that would require Ottawa to press for the return of Canadian Omar Khadr from the U.S. military prison at Guantanamo Bay, Cuba, CBC News has learned.

The government has decided to fight a Federal Court of Appeal decision this month that upheld a lower court ruling, unnamed sources told CBC parliamentary reporter Julie Van Dusen.

The Justice Department has filed a motion for a stay pending appeal, Van Dusen said. No minister was available to comment Monday evening, but the government told CBC News "its position remains unchanged" that "Omar Khadr has been accused by the U.S. of serious crimes including murder."

The Supreme Court will have to decide whether to review the case, Van Dusen said.

The Toronto-born Khadr, now 22, was arrested in Afghanistan in July 2002 when he was 15 years old. He is alleged to have thrown a grenade that caused the death of a U.S. soldier. He has been held at Guantanamo Bay since October 2002, awaiting trial on charges of murder, conspiracy and support of terrorism.

In Edmonton, Khadr's lawyer Dennis Edney told CBC News, "I think it's a mean decision by this government."

On Aug. 14, the Court of Appeal upheld a Federal Court ruling that ordered the Canadian government to press for Khadr's return from Guantanamo.

In a 2-1 judgment, the court found that Khadr's rights under Section 7 of the Charter of Rights and Freedoms — the rights to life, liberty and security of person — had been breached when Canadian officials interviewed him at the prison in Guantanamo and shared the resulting information with U.S. authorities.

Last April, Federal Court Judge James O'Reilly ruled in favour of Khadr's charter challenge of the Canadian government's decision not to request his repatriation from Guantanamo Bay.

The federal government appealed O'Reilly's decision and has long maintained that because of the seriousness of the charges, Khadr should face military proceedings in the United States.

Court of Appeal agrees with judge

The Court of Appeal agreed with O'Reilly that Canada had an obligation to take steps to "protect Khadr from further abuse" and that by refusing to request his repatriation, his charter rights had been violated.

The panel also rejected the Crown's argument that O'Reilly's ruling was a serious intrusion into the conduct of Canada's foreign affairs, as well as the government's claim that there is little chance the U.S. will abide by the repatriation request, since the U.S has complied with similar requests from other Western countries.

In his decision, O'Reilly pointed out that Khadr is the last citizen of any Western country held at Guantanamo. Other countries have repatriated their citizens.

Khadr's lawyers argued the Canadian government was complicit in the detainee's alleged torture and mistreatment while in U.S. custody, and obliged under international law to demand his return.