The youngest inmate of the Guantanamo Bay detention camp has pleaded guilty to killing an American soldier in Afghanistan eight years ago when he was 15.
Omar Khadr, 24, who is a Canadian citizen, was appearing before a military tribunal.
Khadr pleaded guilty to five charges including murder, in a deal with US military authorities.
Details of the plea agreement have not been released, but it could mean Khadr would avoid life in prison.
He might also be returned to Canada to serve a shorter term.
Khadr was accused of killing US Army Sergeant Christopher Speer, from New Mexico, when US troops raided a military compound in Afghanistan in 2002.
The BBC reports his trial began in August, but was delayed when his lawyer fell ill.
He grew up in Canada, Pakistan and Afghanistan and is the son of an al-Qaeda official who was killed in 2003.
Khadr was charged with murder in violation of the laws of war, conspiracy, providing material assistance to a terrorist organisation and espionage.
He also admitted planting improvised explosive devices and receiving weapons training from al-Qaeda.
He repeatedly answered "yes" to questions from the judge, who asked Khadr if he understood the charges against him.