A U.S. military judge has postponed the trial of Omar Khadr, a young Canadian man detained at Guantanamo Bay, Cuba, for the past six years for alleged crimes committed as a teenager.

The trial was supposed to begin next month at Guantanamo Bay, but at a pretrial hearing Thursday the judge announced a schedule change as prosecutors and defence lawyers wrangle over access to evidence and expert witnesses.

The new date has not yet been set.

A spokeswoman for the tribunals, air force Maj. Gail Crawford, said the judge did not immediately explain why he pushed back the Oct. 8 trial date at the U.S. navy base in Cuba.

Khadr was 15 years old when he was taken into custody for allegedly throwing a grenade in a July 2002 firefight at an al-Qaeda compound in Afghanistan that led to a U.S. Special Forces commando's death.

He has been held in Guantanamo Bay for the past six years and faces up to life in prison if convicted of the crimes.

Khadr, now 21, is the only Western foreigner still being held at the naval prison, widely decried as illegal by critics and human rights activists.

Lawyers for Khadr have filed a lawsuit in Federal Court to try to compel the Canadian government to repatriate him, arguing Canada is obliged under international law to ensure Khadr's rehabilitation since he was a child at the time of the alleged crime.

Khadr's case made international headlines in July when video was released showing him sobbing while Canadian Security Intelligence Service officials interrogated him at Guantanamo Bay in 2003.

With files from the Associated Press