Speaking in Saudi Arabia, Secretary of State John Kerry also raised the prospect of military force against Iran. Under questioning from reporters on U.S. aid for Syria rebels, Kerry dismissed concerns it may fall into the wrong hands.

Secretary of State John Kerry: “This is important for Iranians to hear and to understand. We both prefer diplomacy as the first choice, as the preferred choice. But the window for a diplomatic solution simply cannot, by definition, remain open indefinitely. There is no guarantee that one weapon or another might not at some point in time fall into the wrong hands. But I will tell you this, that there is a very clear ability now in the Syrian opposition to make certain that what goes to the moderate, legitimate opposition is in fact getting to them.”

The United States confirmed last week it is providing non-lethal aid and training to Syrian rebels. The CIA is training a group of Syrian opposition fighters in neighboring Jordan.