Israel launched a pre-emptive attack against Iran on Saturday, and a United States attack is underway, plunging the Middle East into a renewed military confrontation and further dimming hopes for a diplomatic solution to Tehran’s nuclear dispute with the West. The U.S. military initiated a series of strikes against targets in Iran, two U.S. officials told Reuters, speaking on condition of anonymity. The scope of the air and sea operations was not immediately clear. Iran was preparing a crushing retaliation, an Iranian official told Reuters. A source told Reuters that Iran’s supreme leader, Ayatollah Ali Khamenei, was not in Tehran and had been transferred to a secure location. The attack follows a 12-day air war in June between Israel and Iran and repeated U.S.-Israeli warnings that the...