After accusing Iran of supporting an assassination plot against Saudi Arabia's ambassador to Washington, the U.S. has issued a worldwide travel advisory for its citizens. In a statement, the State Department has warned Americans of the possibility of an anti-American action by Iran in retaliation of the accusation.

The Department of State alerts U.S. citizens of the potential for anti-U.S. actions following the disruption of a plot, linked to Iran, to commit a significant terrorist act in the United States, the department said in a statement released on its Web site late on Tuesday.

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, the statement added.

The alert expires on Jan. 11, 2012.

Iranian-born U.S. citizen Mansoor Arbabsiar, 56, was being held without bail in New York for his role in the alleged plot to kill Saudi diplomat Adel Al-Jubeir in the United States. Arbabsiar is suspected of working on behalf of the Iranian Islamic Revolutionary Guard Corps Qods Force - designated by the Treasury Department in 2007 for its support of terrorism.