Omar Khadr's Canadian lawyer has blasted CBS News for airing never-before-seen tape that supposedly shows the 21-year-old constructing explosives, saying the footage from a 60 Minutes special subtitled "The Youngest Terrorist?" violated a court ban.

Dennis Edney, a lawyer for the Toronto-born detainee, said a U.S. judge had already ruled the video could not be admissible as evidence for Khadr's terrorism trial at the U.S. naval base in Guantanamo Bay.

On Sunday evening, however, the CBS current affairs program aired a feature on Khadr, using video images that 60 Minutes said "appears to be Omar Khadr helping put together a firing device."

The footage showed a group of men sitting indoors on the floor, where gadgets and wires are strewn about. One clip appears to show a young man fanning himself and handling a roll of tape, and another clip shot in night-vision shows a man apparently burying a landmine.

Khadr was only 15 years old in July 2002, when U.S. authorities allege he threw the grenade that fatally wounded a U.S. medic in eastern Afghanistan. Khadr was found alive in the rubble of a bombed-out building shortly afterwards, and was detained at the Guantanamo Bay base in Cuba, where he has since been charged with murder.

The military had reportedly been long planning to show the seized videotape during trial. Edney told the Canadian Press he believed the U.S. government leaked the tape to 60 Minutes to circumvent the court's ruling that the tape could not be considered as evidence.

Military trial delayed

Edney, who was also interviewed during the 60 Minutes special, told the Canadian Press he was outraged after learning the video ran with the piece broadcast on Sunday.

Khadr's military trial at Guantanamo Bay had been delayed since June, when a U.S. judge dropped all charges against the Canadian based on a technicality and a ruling that the court did not have the proper jurisdiction to try the Canadian. In September, a U.S. military appeal court overruled the earlier decision and reinstated the murder, terrorism and spying charges against Khadr.

Khadr's trial began again earlier this month. If found guilty, he faces life imprisonment.

With files from the Canadian Press