The US defence secretary has acknowledged for the first time that he supports arming Syrian rebels.
In testimony to Congress, Leon Panetta said he still supported the supply of weapons to rebels fighting forces loyal to Syrian President Bashar al-Assad.
The plan was proposed by then-Secretary of State Hillary Clinton and David Petraeus, then director of the CIA, but reportedly rebuffed by the White House.
The US has so far offered only diplomatic backing to Syria's rebels.
More than 60,000 people are estimated to have been killed in the 22-month conflict.
The UN says it fears continuing violence could destabilise the whole region, and more than 600,000 Syrians have fled into neighbouring countries.
Nod of assent
Mr Panetta's admitted support for the arming of Syria's rebels during testimony to the Senate Armed Services Committee.
The hearing - which centred on the attack on the US consulate in Benghazi, Libya, in September 2012 - is likely to be Mr Panetta's last before he leaves office.
He was asked directly by Republican Senator John McCain whether he and the Pentagon backed the Clinton plan.
Sitting next to Gen Martin Dempsey, chairman of the Joint Chiefs of Staff, Mr Panetta nodded and said: "We do."
Commenting on Twitter, Mr McCain called the admission "interesting".
The Clinton-Petraeus plan to arm the rebels was hatched during the summer of 2012, the New York Times reported recently.
The pair conferred as criticism grew of US inaction over the situation in Syria, and as the country's bitter civil conflict claimed ever more lives.
They proposed a plan to arm carefully vetted rebel groups, which they hoped would win them allies within the rebel ranks, the Times said.
But the plan was shelved by the White House during the US election campaign, the paper reported, amid concerns about weapons falling into the wrong hands - including radical rebel elements affiliated with al-Qaeda.
The BBC's Kim Ghattas in Washington says Mr Panetta's remark is the first time a senior American official has publicly taken this position.
Washington has so far refused to give military backing to the rebels, limiting itself to political support. But US allies like Qatar and Turkey are arming the rebels with Washington's tacit approval, she adds.
Mr Panetta is stepping down, with Chuck Hagel nominated as his successor.
Mr Hagel, a former Republican senator who broke with his party over the Iraq war, endured a testy confirmation hearing last week.
No vote has yet been scheduled for his confirmation.