WASHINGTON (AP)-- John Kerry says it's up to Iran to prove that its nuclear program is for peaceful purposes.
The Massachusetts senator testified today to his colleagues on the Senate Foreign Relations Committee, at a confirmation hearing on his nomination to be secretary of state.
He said President Barack Obama has made it clear that "we will do what we must to prevent Iran from obtaining a nuclear weapon." Kerry added that "the clock is ticking on our efforts to secure responsible compliance."
Kerry says he's still hopeful that the U.S. and other nations can make progress on the diplomatic front.
On another issue, Kerry was asked about his past outreach to Syria's Bashar Assad -- but he said that's all irrelevant now because of Assad's unending violence against his citizens amid a two-year civil war. He said he doesn't think Assad has much time left as Syria's leader.
Republican Sen. John McCain -- a critic of Obama's policy on Syria -- told Kerry that the U.S. needs to do more to help rebels there, even if it doesn't send ground troops.
Kerry said the U.S. needs to continue discussions with Russia and others about Syria -- but he said he's not optimistic.