
Beheshti is the younger son of Ayatollah Mohammad Hossein Beheshti, one of the main leaders of the 1979 Islamic Revolution and a top judge who was killed in an anti-regime bombing in 1981.
The British-trained academic does not wield the influence of some of the clerics who have criticized the election, but a call for the president's removal is a rarity in Iran and indicates the opposition is remaining firm in the face of increased pressure from the ruling clerics.
Iason Athanasiadis, the reporter freed Sunday, had been detained because of "behavior violating the profession of reporting," Foreign Ministry spokesman Hasan Qashqavi said, according to a report on Iran's state television. He did not elaborate.
Athanasiadis, who has British and Greek citizenship, had entered Iran a previous time on his British passport and was barred from returning for "violating the law," the TV report quoted Qashqavi as saying.
On this recent trip, he was arrested on or around June 19, a day before the clashes between protesters and security forces reached their peak.
Greek Foreign Minister Dora Bakoyannis said: "I am deeply satisfied over the release of Iason Athanasiadis. ... (We were) in constant, close contact with the Iranian Foreign Ministry."
Athanasiadis' parents, in appealing for his release, called him a reporter, photographer and filmmaker with "a particular love of Iran, and a deep respect for its cultural and religious traditions."
"We are encouraged by reports that Iason has been released and are awaiting confirmation," said Joel Simon, executive director of the Committee to Protect Journalists. "However, about 20 journalists remain in prison in Iran, and we hope they will be released soon."
Newsweek correspondent Maziar Bahari, who has Iranian and Canadian citizenship, is among the journalists still being held. He has been charged with "agitating against the ruling system and acting against national security," his lawyer Saleh Nikbakht said on Saturday.