TORONTO - The group that oversees Ontario's lawyers is calling on Prime Minister Stephen Harper to ask the U.S. to return Omar Khadr to Canada.

Khadr, the only Canadian citizen being held in Guantanamo Bay, is due to stand trial Jan. 26 for war crimes.

The U.S. accuses him of throwing a hand grenade that killed an American army medic following a fierce four-hour firefight in Afghanistan in July 2002.

Derry Miller, treasurer of the Law Society of Upper Canada, says the group believes Khadr, now 22, should be returned to Canada and put on trial here.

In a Nov. 6 letter to Harper, Miller notes that U.S. president-elect Barack Obama is on the record as being opposed to the operation of the Guantanamo Bay prison.

Miller says the law society believes this makes it an opportune time to raise the issue with the U.S.

"The Law Society of Upper Canada regards adherence to the rule of law and due process as fundamental principles that are the right of every Canadian citizen, regardless of the character or circumstances of the citizen," Miller writes.

Khadr should be "returned to Canada, where he can be tried by a regularly constituted court affording all the judicial guarantees recognized" by the Geneva Conventions," the letter states.

Harper has repeatedly said he would not interfere.

The Canadian government has also maintained the Americans have reassured Ottawa of Khadr's humane treatment.

Khadr, who was 15 at the time he was captured, was badly wounded and near death when he was captured.

Ottawa has said it pressed the Americans to ensure his proper medical care, to take his age into account, and to allow him access to Canadian lawyers.

In a May 2008 ruling, the Supreme Court of Canada said there have been "clear" violations of fundamental human rights in the Khadr case.

And in July 2008, documents revealed Khadr was deprived of sleep for weeks to soften him up for interrogation.

Department of Foreign Affairs reports say Canadian official Jim Gould visited Khadr in Guantanamo Bay in 2004 and was told by the American military that measures were taken to make the then-17-year-old more pliable for interviews.