U.S. Secretary of State John Kerry delivered an ardent defense Monday of President Barack Obama as a strong foreign policy leader and "man of his word," whose guarantee that Iran will never be allowed to obtain a nuclear weapon should be heeded by doubters.

"Every time the president has said, 'I'm going to do something,' he has done it," Kerry said at a news conference with United Arab Emirates Foreign Minister Abdullah bin Zayed al-Nahyan. Obama's Iran pledge, he said, "is a centerpiece of his foreign policy, and he will not bluff."

Kerry's remarks were clearly directed both at Israel, which has launched an international campaign to stop a potential U.S.-led nuclear deal with Iran from being finalized, and U.S. lawmakers who charge that such an agreement will harm both American and Israeli security.