Toronto, Nov 1 (IANS) Afghan Canadian Omar Khadr, the only child soldier and last western prisoner held at Guantanamo, has been sentenced to 40 years in jail for killing a US medic in Afghanistan in 2002.

Twenty-four-year-old Khadr, whose father was a close aide of Al Qaeda chief Osama bin Laden, was 15 when he was arrested in a gunbattle with the US forces in Afghanistan in 2002.

The Afghan Canadian, whose detention by the Americans as the first child soldier since World War II was strongly criticised by left-wing Canadian media and opposition parties, had pleaded guilty to killing the US medic and all terror charges last Monday before a military tribunal at Guantanamo.

Tabitha Speer, the widow of US medic Christopher Speer who was killed by Khadr, was in court Sunday when the military panel handed down the 40-year jail term to her husband's killer.

"You will forever be a murderer in my eyes. It doesn't matter what you say from this day on. I hear over and over how he's the victim, he's the child. I don't see that. The victims -- the children -- are my children. Not you. They're the ones hurting. You made a choice; my children had no choice," the widow had said in her testimony Thursday.

In response, Khadr had apologised to her, saying, "I am really, really sorry for the pain I've caused you and your family. I wish I could do something that would take this pain away from you."

The young terrorist's father, Ahmed Said Khadr, was a one-time associate and financier of Osama bin Laden and was killed in Pakistan in 2003.

The Khadr family moved to Canada from Egypt in 1977, but because of their dislike of western values, they moved to Peshawar in Pakistan in 1988. In between, the family lived in Toronto.