McCain explodes at US ambassador over Syria

McCain also objected to Ford's assessment that Syrian rebels are grateful for America's $385 million in humanitarian aid. Syrians he's met in refugee camps, McCain said, are “angry and bitter” at the administration's refusal to provide arms to the rebels.

The panel's chairman, Sen. Robert MenendezRobert MenendezTim Kaine backs call to boost funding for Israeli missile defense GMO labeling bill advances in the Senate over Dem objections Overnight Finance: Trump threatens NAFTA withdrawal | Senate poised for crucial Puerto Rico vote | Ryan calls for UK trade deal | Senate Dems block Zika funding deal MORE (D-N.J.), on Thursday became the latest lawmaker to join calls to arm the rebels. 

Ford said the administration's policy is to support the opposition through non-lethal means. He said a negotiated political settlement that guarantees a place for the Alawite minority and regime supporters in a future Syria is the only way to end the conflict.

"If there is not a negotiated settlement," Ford said, "our sense is that regime supporters, fearing death, will fight to the death."