NEW : `` What are they developing these -- building these enormous underground nuclear facilities , if not for a nuclear weapon ? '' Iranian Prime Minister says U.S. is obviously trying to build nuclear weapons . Kerry says Germany and Iran `` great friends '' amid spy flap . Top Iranian official says his country does n't need to build nuclear weapons . Kerry says it 's vital to ensure `` Iran is not going to develop a nuclear weapon ''
NEW : Iranian Prime Minister says U.S. is obviously trying to build nuclear weapons . Kerry says Germany and Iran `` great friends '' amid spy flap . Top Iranian official says his country does n't need to build nuclear weapons . Kerry says it 's vital to ensure `` Iran is not going to develop a nuclear weapon ''