A former member of Iran's largest reformist student group, the Office To Foster Unity, has been detained in Tehran.
RFE/RL's Radio Farda reports that Said Razavi Faghih was arrested on February 2, several days after returning from France, where he attends university.
His passport was confiscated by officials when he arrived in Tehran on January 28 and he was detained after being summoned to a revolutionary court.
He has been transfered to Tehran's Evin prison.
The reason for his arrest and the charges against him are unclear.
Razavi Faghih had in the past worked with several reformist publications. He has been studying in France for the past five years.
He had not encountered any problems with authorities during his previous three trips to Iran.