The State Department late issued a worldwide travel alert for U.S. citizens, warning of the potential for anti-U.S. action after the United States accused Iran of backing a plot to kill Saudi Arabia's ambassador to Washington.
"The U.S. government assesses that this Iranian-backed plan to assassinate the Saudi ambassador may indicate a more aggressive focus by the Iranian government on terrorist activity against diplomats from certain countries, to include possible attacks in the United States," it said in a statement on its website.