DUBAI, United Arab Emirates — Iranian Supreme Leader Ayatollah Ali Khamenei was killed in a major attack on Iran launched by Israel and the United States, President Donald Trump said Saturday on social media. Trump said his death is “the single greatest chance for the Iranian people to take back their Country.” The death occurred after a joint U.S. and Israeli aerial bombardment that targeted Iranian military and governmental sites. The president also said “heavy and pinpoint bombing” was to continue “uninterrupted” through the week or longer. There was no immediate comment from Iran. The assassination of the second leader of the Islamic Republic, who had no designated successor, would throw its future into doubt and raise the prospect of a protracted conflict given Iranian threats of retaliation. Trump in his post called Khamenei “one of the most evil people in history.” Trump said that Khamenei “was unable to avoid our Intelligence and Highly Sophisticated Tracking Systems and, working closely with Israel, there was not a thing he, or the other leaders that have been