Iran ? Iran has formally charged three Americans with espionage and endangering national security, the government’s judicial spokesman said Tuesday, signaling a widening clampdown against U.S. citizens in Iran.

The three individuals charged are prominent Washington scholar Haleh Esfandiari, social scientist Kian Tajbakhsh of the New York-based Open Society Institute, and correspondent Parnaz Azima of the U.S.-funded Radio Farda.

Iran announced over the weekend that it had uncovered U.S. spy networks and protested to the Swiss ambassador, who represents U.S. interests in Iran.

Secretary of State Condoleezza Rice called the charges a “perversion of the rule of law,” while a State Department spokesman Tuesday said that the charges are “absurd” and appealed to Tehran to immediately free the Americans.