WASHINGTON - A U.S. military judge has rejected a bid by defence lawyers to dismiss charges against Canadian Omar Khadr because he was only 15 years old at the time of his alleged offences.

Col. Peter Brownback issued the ruling today.

Defence lawyer Lt.-Cmdr. William Kuebler argued three months ago that prosecuting Khadr contravenes international law, including the Child Soldier Protocol signed by the United States.

Now 21, Khadr has been held since October 2002 at the U.S. prison camp in Guantanamo Bay, Cuba.

He faces life in prison for allegedly throwing a hand grenade that killed a U.S. soldier in Afghanistan in a July 2002 firefight.

Kuebler, who appeared before a Canadian parliamentary committee this week, called the ruling an embarrassment for the United States.