The U.S. military struck three sites in Iran early Sunday, directly joining Israel's war aimed at decapitating the country's nuclear program in a risky gambit to weaken a longtime foe amid Tehran's threat of reprisals that could spark a wider regional conflict. Addressing the nation from the White House, President Donald Trump said Iran's key nuclear sites were "completely and fully obliterated." He also warned Tehran against carrying out retaliatory attacks against the U.S., saying Iran has a choice between "peace or tragedy."