WASHINGTON (AFP) – The US Senate Armed Services Committee unanimously approved Leon Panetta's nomination to be US defense secretary on Tuesday, setting the stage for a full senate confirmation.

Panetta, 72, who has served President Barack Obama as CIA chief, was expected to sail to confirmation by the full US Senate, though the precise timing of a final vote was not yet clear.

In a break with outgoing Pentagon chief Robert Gates, Panetta said last week that he supported the withdrawal of a significant number of troops from Afghanistan next month.

Obama is currently weighing how quickly to withdraw troops from Afghanistan as the military works to put Afghans in charge of their own security by 2014 and wrap up what is now an almost decade-long war.

The president has said the withdrawal of troops will begin in July, but that the timetable would be determined by conditions on the ground.

Panetta is on track to replace Gates July 1 and be succeeded as CIA chief by General David Petraeus, now the US commander in Afghanistan.

Recent months have seen mounting US opposition to the war in Afghanistan, where the United States has some 100,000 troops nearly ten years after invading the country to capture or kill Al-Qaeda chief Osama bin Laden.

Support for withdrawing US forces has spiked since US commandos killed bin Laden in his Pakistan hideout last month.