A reporter for U.S.-funded Radio Farda who had been trapped for months in Iran left the country Tuesday, returning to the United States, the station said.

Parnaz Azima was one of four Iranian-Americans suspcted by Iran of involvement in a plot to foment a revolution against the Islamic government. Another of the four was released earlier.

Azima "left Iran today and is on her way to the United States," Sania Winter, a spokeswoman for Radio Free Europe-Radio Liberty, told The Associated Press from Washington. She would not give further details.

Unlike the other three Americans, Azima -- who works for RFE-RL's Farsi-language service Radio Farda -- was not imprisoned in Iran but authorities confiscated her passport when she arrived in the country in January on a family visit.

All four Americans were charged with endangering national security, an accusation they denied. The station said Tuesday that the charges against Azima have not been dropped and that the deed to her mother's house in Tehran, offered in lieu of $550,000 in bail, has not been returned. Her passport was returned to her Sept. 4.

The charges have heightened tensions between the United States and Iran, already high over U.S. accusations that Tehran was seeking to develop a nuclear weapons and is fueling violence in Iraq. Iran denies both claims.

But Iranian authorities appear to be aiming to defuse the crisis. Scholar Haleh Esfandiari was released on Aug. 21 from Tehran's Evin prison, where she had been held for months. Esfandiari left the country early the next month.

Last week, journalists were allowed to see another of the Americans, Kian Tajbakhsh, during a visit to Evin prison. Tajbakhsh said he expected to be freed soon, and an Iranian judiciary spokesman said his release was likely.

Also still being held at Evin is Ali Shakeri, a member of a California-based democracy group, the Center for Citizen Peacebuilding. Iranian officials have not said anything about his release.