TORONTO -- A "trigger-happy" U.S. army squad leader shot the foot off an unarmed Iraqi man and soldiers kicked a severed head around like a soccer ball, a U.S. war deserter told an Immigration and Refugee Board hearing yesterday.

Joshua Key, the first U.S. deserter with combat experience in Iraq to apply for refugee status in Canada, told the board he witnessed numerous atrocities committed by U.S. forces while serving eight months as a combat engineer.

Key, 27, said there was never any discussion about the Geneva Convention during his training and he was told in Iraq by superior officers that the international law guiding humanitarian standards was just a "guideline."

"It's 'shoot first, ask questions later,' " Key said of his squad's guiding principles. "Everything's justified."

Key is one of five members of the U.S. armed forces asking for asylum in Canada.

But the Oklahoma native is unique in that he is the only applicant who has combat experience in Iraq, said his lawyer, Jeffry House. The others are seeking asylum in Canada to avoid being sent there, he said.

Key shouldn't have to return to the U.S. because the consequences of his decision to desert the war would likely amount to persecution, given the things he witnessed in Iraq, House said.

"He has boots-on-the-ground experience about what the actual conduct of the war in Iraq is," House said outside the hearing.

"If you have to participate in atrocities and you're going to be punished for refusing to participate in atrocities, then that punishment is illegitimate and it becomes persecution."

Key told the hearing he suffers from post-traumatic stress disorder and frequently has nightmares over what he witnessed in Iraq.

He recalled participating in almost nightly raids on homes of suspected insurgents in Ramadi and Fallujah as a member of the 43rd Combat Engineer Company.

He said that while the raids seldom turned up anything of interest, he often saw soldiers ransack the homes and steal jewelry or money, while superior officers looked the other way.

He also said several Iraqis were killed because of soldiers "shooting out of fear and inventing reasons afterward."