A video of a weeping Canadian teenager being interviewed at Guantanamo Bay over the killing of a US soldier has been released.

The interrogation, by Canadian intelligence officers, is believed to be the first from the base seen by the public.

Omar Khadr's lawyers released excerpts of their client being questioned at Guantanamo Bay in 2003.

In the video released via the internet, a Canadian Security Intelligence Services agent is shown grilling Khadr, 15, about events leading up to his capture as an enemy combatant.

Khadr, a Canadian citizen, is accused of throwing a grenade that killed a US soldier during a 2002 firefight in Afghanistan.

The video shows Khadr weeping, his face buried in his hands.

At one point, Khadr tells them he was tortured while at the US military detention centre at the Bagram air base in Afghanistan, where he was first detained after his arrest in 2002. He raises his orange shirt to show the wounds he sustained.

He also tells the agent: "You don't care about me."

The video provides insight into the effects of prolonged interrogation and detention on the Guantanamo prisoner.

The seven-hour video, taken over four days of interviews, was originally marked "Secret/No Foreign."