Iran has released Iranian-American peace activist Ali Shakeri after he spent four months in a Tehran prison, a judiciary spokesman said Tuesday.

Shakeri is the fourth U.S. citizen to be released by Iran since August after being accused of trying to stir up a revolution.

Ali Shakeri spent four months in a Tehran prison after being accused of trying to stir up a revolution.
(Center for Citizen Peacebuilding, Paul R. Kennedy/Associated Press)

He was released Monday night on the equivalent of about $110,000 in bail and is allowed to travel abroad, Mohammad Shadabi, a spokesman for the judiciary, told the Associated Press.

Shakeri, a businessman and member of a California-based democracy group, the Center for Citizen Peacebuilding, had been on his way back to America after visiting his mother, who died while he was in Iran, when he was jailed in Tehran's Evin prison four months ago.

He was one of four Iranian-Americans charged with endangering national security — an accusation the four suspects, their families and their employers denied.

The charges have increased tensions between the United States and Iran, which are already high because of U.S. accusations that Iran is seeking to develop nuclear weapons and is fuelling violence in Iraq.

Iran denies both claims.

But in recent weeks, the country has shown a change of heart toward the cases against the four dual citizens, and Tuesday's announcement comes as Iranian President Mahmoud Ahmadinejad is in New York City to attend the UN General Assembly.

Shakeri's release comes less than a week after Iran released Kian Tajbakhash, an urban planning consultant with the New York-based Soros Foundation's Open Society Institute, from Evin prison where he had been jailed for four months.

In August, Iranian-American academic Haleh Esfandiari, who is the director of the Washington-based Woodrow Wilson International Center for Scholars, was also released from the prison, while Iranian-American journalist Parnaz Azima was allowed to leave the country after being trapped since authorities confiscated her passport in January.

Authorities never imprisoned Azima, but prevented her from leaving the country.

Also this week involving a separate case, the Iranian government said it would allow the wife of a missing American who once worked for the FBI to travel to Iran even though it has no information on his whereabouts.

Robert Levinson was last seen March 8 on Kish Island, a resort off the southern coast of Iran, where he had gone to seek information on cigarette smuggling for a client of his security firm. His wife believes he did not leave Iran.