A U.S. military commander modified a report on a firefight in Afghanistan to pin the blame for a U.S. soldier's death on Omar Khadr, a defence lawyer alleged Thursday.

The lawyer, Navy Lt. Cmdr. William Kuebler, made the allegation at a pretrial hearing at the U.S. military base in Guantanamo.

Kuebler was arguing for access to the military commander, who has been identified only as Col. W., as well as for details about interrogations that could help clear his client of war-crimes charges, he said.

Omar Khadr was interrogated after he was captured following a gunfight with U.S. troops.

Khadr, the Toronto-born son of an alleged al Qaeda financier, is in Guantanamo Bay awaiting trial on murder and conspiracy charges based on allegations he threw a grenade during the firefight in 2002, killing one of the U.S. soldiers. He was just 15 at the time.

The military commander's official report, the day after the raid, initially said the assailant who lobbed the grenade was killed, which would clear Khadr of suspicion.

The report was altered months later, under the same date.

The revised report said a U.S. fighter had only "engaged" the assailant, Kuebler alleged.

Kuebler said prosecutors offered him the revised version as an "updated document."

Kuebler told reporters after the hearing that it appears "the government manufactured evidence to make it look like Omar was guilty.''

But Army Col. Bruce Pagel, the deputy chief prosecutor for the Guantanamo tribunals, dismissed those suggestions, saying the government didn't fabricate evidence.

Pagel would not discuss the report further, citing it as trial evidence.

Dennis Edney, Khadr's Canadian lawyer, suggested on CTV's Canada AM that U.S. prosecutors are relying on statements that were extracted from Khadr under duress in 2002 at Bagram prison.

Edney said two other prisoners actually died from interrogation tactics during the period Khadr was at the prison.

The lawyers want the interrogators named as part of their efforts to determine whether Khadr was forced into making the statements.

Khadr's interrogators included members of a unit implicated in the December 2002 beating deaths of two Afghan detainees, named Dilawar and Habibullah, Kuebler said.

"We learned today that those interrogations were conducted by members of the military intelligence unit whose members were implicated in numerous allegations of detainee abuse in Bagram, and in fact the deaths of two detainees," Kuebler told CTV Newsnet from Guantanamo Bay.

"We've asked for information in the government's possession relating to detainee abuse at Bagram, we've asked for information in the government's possession relating to the names and identities of the interrogators who conducted interrogations of Omar in August and September of 2002," he added.

Edney said the charges against his client are based on flimsy evidence.

"As we now know, contrary to what the administration has been saying for years, there is no eyewitness who can say Omar Khadr threw a hand grenade at anybody," Edney said from Edmonton.

"And we also know Omar Khadr was not alone in that compound when it was attacked by the Americans."

He said Khadr was suffering from three bullet wounds, was made to sit up in bed during questioning, and was made to carry buckets of water up and down a hallway during his interrogation in Afghanistan.

"We also know he was used as a human mop to mop up urine and we know he was handcuffed and tied to the entrance of a doorway with his arms raised for long periods of time. It's that type of treatment he received and others received," Edney said.

At the pre-trial hearing on Thursday, Kuebler showed the judge a photograph of Khadr after he was captured. The image showed exit wounds in his chest from gunshots to his back.

"We're not talking about an adult of able physical and mental condition,'' he said.

Khadr's lawyers have argued he should never have been jailed with adults at the U.S. naval base in Cuba, and deserves more lenient treatment.

However, military prosecutors argue the men need to be held accountable, and say there is no age cutoff under the 2006 law that allowed the military to hold war crimes tribunals at Gitmo.

Lead prosecutor, Marine Corps Maj. Jeffrey Groharing, said Thursday that defence lawyers have not proved that speaking with individual interrogators would help their case.

He told the hearing that the government has already presented typewritten summaries of the Bagram interrogations.

The judge, Army Col. Peter Brownback, is expected to rule on most of the defence motions by late Friday. The trial is currently scheduled for May but the defence's evidence-related requests could delay proceedings.

Brownback also told prosecutors to provide the defence official correspondence on the case between the U.S. and Canadian governments.

With files from The Associated Press