Iranian Supreme Leader Ali Khamenei was killed in an Israeli strike Saturday as part of a massive joint military operation between the U.S. and Israel, Israel's ambassador to Washington told U.S. officials. An Israeli official confirmed to Axios that Khamenei is dead, according to Israeli intelligence. Why it matters: The 86-year-old Khamenei led Iran for 35 years, making him one of the world's longest-serving authoritarian rulers. His death is a massive blow to the regime and could accelerate its collapse, which U.S. and Israeli officials have stated as a goal of their operation.