Iranian-American who recently visited Iran missing

WASHINGTON, May 25 (Reuters) A dual US and Iranian citizen who visited Iran this year has not been heard from since March and a California institute he is affiliated with said it was concerned about his whereabouts.

Ali Shakeri is a California businessman who serves on an advisory board to the Center for Citizen Peacebuilding at the University of California at Irvine, which studies how citizens can promote peace in divided societies.

News he has gone missing comes after at least three Iranian-Americans have been arrested, detained or otherwise prevented from leaving Iran in recent months in what appears to be an Iranian crackdown on dual citizens.

Diplomats fear the detentions, which follow the US military's arrest of five Iranians in Iraq in January, could herald further deterioration in relations between the two countries, which have not had diplomatic ties since 1980.

Paula Garb, the co-director of the Center for Citizen Peacebuilding, said Shakeri went to Iran earlier this year and had been expected to return several weeks ago.

''We haven't heard from him since March 8 and we were expecting him back a couple of weeks ago,'' Garb said, adding she did not know where he was and was concerned about his whereabouts.

In a report issued yesterday, rights group Human Rights Watch quoted unidentified associates of Shakeri as saying he was ''being detained by the Iranian authorities.'' Dual citizens arrested, detained or otherwise kept from leaving Iran include Haleh Esfandiari, a scholar at the US Woodrow Wilson International Center for Scholars think tank; Parnaz Azima, a reporter for US-funded Radio Farda; and Tehran-based social scientist and urban planner Kian Tajbakhsh, a consultant to the New York-based Open Society Institute.

A fourth dual citizen is also believed to have been kept from leaving Iran but has not been named by the US government. A State Department spokesman declined comment on Shakeri's case and it was unclear if he was the fourth person.

US officials also believe Tehran may be holding former FBI official Robert Levinson, who disappeared early in March while on a visit to the Iranian island of Kish. Iran has denied it is holding him.

The detentions take place amid tension between the United States and Iran over Iran's nuclear programme, which the West suspects is aimed at making atom bombs. Iran denies that, saying it wants nuclear power to generate electricity.

The two countries, which cut ties after Iran's 1979 Islamic Revolution, are also at odds over Iraq, where Washington accuses Tehran of fomenting the insurgency and of providing sophisticated roadside bombs that have killed US soldiers.

US forces in Iraq detained five Iranians in a raid in January and said they were linked to Iranian Revolutionary Guard networks that provided weapons to insurgents. Iran has said the five were diplomats and has demanded their release.

REUTERS SZ PM0625