A US military jury on Thursday rejected government prosecutors' demands for a stiff sentence for Osama bin Laden's ex-driver, Salim Hamdan, saying he should only spend another five months in prison for supporting terrorism.

US prosecutors on Thursday called on a military jury to jail Osama bin Laden's former driver Salim Hamdan for at least 30 years, if not life.

Military jurors found Osama bin Laden's former driver Salim Hamdan not guilty on Wednesday on terrorist conspiracy charges but convicted him on the lesser charge of providing material support to terrorism.

Prosecutors at the first Guantanamo war crimes trial have said in closing arguments that a former driver for Osama bin Laden offered the terrorist leader aid and protection that helped make possible the September 11 attacks.

Laden's former driver Salim Hamdan testified at his war crimes trial that the nine-hour interrogation focused almost entirely on whether he swore an Islamic oath or bayat to his boss, but he refused to discuss the topic.

A military judge penalised US prosecutors by blocking their use of a May 2003 interrogation as they finished presenting evidence in the first Guantanamo war crimes trial.

The first Guantanamo war crimes trial began on Monday with a not guilty plea from a former driver and alleged bodyguard for Osama bin Laden.