WASHINGTON - Canadian terror suspect Omar Khadr says he was forced to implicate himself in a bid to placate U.S. interrogators who he said shackled him for hours, spit on him, dropped him and threatened him with rape.

In an affidavit released Tuesday, Khadr outlined in detail what he says happened after he was captured during a firefight in Afghanistan on July 27, 2002. The battle ended with American soldiers shooting him twice in the back.

Unconscious for a week afterward, Khadr said the interrogations in Bagram began while he was still on a stretcher and that he cried because of the pain inflicted during questioning.

Canadian officials who later visited him at the U.S. prison camp in Guantanamo Bay did nothing to help him, said Khadr, but instead called him a liar and screamed at him.

Many of the specifics of the measures allegedly used by U.S. soldiers were blacked out by the military before the eight-page document was made public.

But it said Khadr "figured out right away that I would simply tell them whatever I thought they wanted to hear'' in order to keep from being abused.

Khadr, then 15 years old, estimates he was questioned 42 times during the three months he spent at the U.S. facility in Bagram near Kabul before he was transferred to Guantanamo.

His chief interrogator at Bagram was revealed last week at a military commission hearing to be Sgt. Joshua Claus, who was court-martialled and discharged from the U.S. army after an Afghan prisoner was beaten to death.

Khadr also accused guards in Guantanamo Bay of smothering him until he blacked out and grabbing him by pressure points on his neck when he was weak from a hunger strike.

He faces life in prison for allegedly throwing the grenade that killed Sgt. Christopher Speer.

His defence lawyer, Lt.-Cmdr. William Kuebler, said Tuesday it makes no sense that Canada has refused to intervene in the case given evidence of how he was abused.

"Any information obtained as a result of such treatment could not be used to prosecute an American citizen in a regular court,'' said Kuebler.

"Yet the Canadian government continues to support the view that such a process is good enough for a Canadian.''

A U.S. Defence Department spokesman said the military's policy is to treat detainees humanely and al-Qaida training documents teach operatives to make false claims of abuse to garner public sympathy.

"Credible allegations of abuse are investigated,'' said Cmdr. J.D. Gordon. "However, in this case we have no evidence to substantiate these claims.''

Khadr doesn't name any of his interrogators at Bagram but refers to a young blond man with glasses and a small tattoo on top of his forearm.

Interrogators pulled him off his stretcher, threw cold water on him and brought barking dogs into the room while his head was covered with a bag, said Khadr.

They forced him to carry heavy buckets of water while he was still wounded and woke him up in the middle of the night to clean the floor and dry it until dawn.

"On several occasions at Bagram, interrogators threatened to have me raped or sent to other countries like Egypt, Syria, Jordan or Israel to be raped,'' Khadr said.

"Many times, during the interrogations, I was not allowed to use the bathroom and was forced to urinate on myself.''

Some of Khadr's allegations about his treatment have become public over the years through his lawyers, including one instance in Guantanamo when he was dragged back and forth like a human mop through a mixture of urine and pine oil on the floor.

Khadr said he wasn't fed for two nights a day before he was put on a plane for Guantanamo so he wouldn't have to use the bathroom.

"Everyone had cuts on their ankles from the shackles,'' he said. "They would smack you with a stick if you made any wrong moves.''

Two soldiers who took charge of him at the prison camp repeatedly pushed his masked face into a wall until he passed out.

"I knew what answers made interrogators happy and would always tailor my answers based on what I thought would keep me from being harmed,'' he said.

He was visited numerous times by people who said they were Canadian government officials, including four visits during four days in a row starting on March 27, 2003.

"I showed them my injuries and told them that what I had told the Americans was not right and not true,'' he said.

"I said that I told the Americans whatever they wanted me to say because they would torture me. The Canadians called me a liar and I began to sob. They screamed at me and told me that they could not do anything for me.''

On a subsequent visit, Khadr said one of the Canadian men told him: "The U.S. and Canada are like an elephant and an ant sleeping in the same bed and that there was nothing the Canadian government could do against the power of the U.S.''

Life "got much worse,'' said Khadr, after he told U.S. interrogators that his previous statements were untrue.

One interrogator pulled his hair and spit in his face. He spent a month in isolation and during interrogations was short-shackled by his hands and feet for five to six hours at a time.

An Afghan interrogator, meantime, told him that he "would be sent to Afghanistan and raped.''

Another told him he'd be sent to Israel, Egypt, Jordan or Syria, "comments that I understood to be a threat of torture.''

When he was weakened by a hunger strike, said Khadr, Guantanamo guards would grab him by pressure points behind his ears, under his jaw and on his neck.

"On the scale of one to 10, I would say the pain was an 11. They would often knee me repeatedly in the thighs.''

Khadr said he was first visited by lawyers in November 2004.