Canada asked the United States not to send former child soldier Omar Khadr to Guantanamo after he was captured in Afghanistan in 2002, according to a letter released Thursday.

In the document dated September 2002, Ottawa argued that the prison camp in Cuba was an "inappropriate" place for Khadr, a Canadian citizen, because he was just 15 years old at the time.

The letter was submitted in court filings by defence lawyers who have urged the Canadian government to demand Khadr's return from Guantanamo Bay, where he is expected to face a military trial by this summer on charges of killing a U.S. soldier.

"It's certainly shocking as we sit here today that Canada is the last western country to tolerate the detention of one of its citizens at Guantanamo Bay," said navy Lt.-Cmdr. William Kuebler, Khadr's Pentagon-appointed lawyer. He has argued that his client cannot receive a fair trial at Guantanamo.

Canada's government has faced pressure to ask for Khadr's transfer, but the Foreign Affairs Department said it would be premature to intervene as long as he is facing charges.

The letter from the Canadian Embassy in Washington to the State Department was dated Sept. 13, 2002, during Khadr's detention at a U.S. military prison in Bagram, Afghanistan. The al-Qaeda suspect had been captured two months earlier during a firefight in which he allegedly hurled a grenade that killed Army Sgt. 1st Class Christopher Speer. He arrived at Guantanamo in October 2002.   

The letter notes that the U.S. and Canada have laws providing for special treatment of young suspects.   

"As such, the Government of Canada believes it would be inappropriate for Mr. Omar Khadr to be transferred to the detention facilities at the American naval base at Guantanamo Bay," the letter said.

The letter also expressed concern over "ambiguity" in early accounts of Khadr's role in the events leading up to his capture. A section that apparently describes the conflict was edited.

Khadr's lawyers are seeking access to additional diplomatic correspondence between Canada and the United States in search of evidence that could help exonerate him. They argue that no witness saw Khadr throw the grenade.

Khadr, the son of an Egyptian-born alleged al-Qaeda financier, is expected to be the first or second detainee to face a U.S. war-crimes tribunal since the Second World War. He faces a maximum sentence of life in prison if convicted on charges including murder, conspiracy and supporting terrorism.

The U.S. military says it plans to charge about 80 of the roughly 275 detainees at Guantanamo, but so far no case has gone to trial.