An influential group of Iranian clerics took sides late Saturday, calling June's re-election of President Mahmoud Ahmadinejad, and by extension his government, illegitimate.

On Sunday, Tehran released a British-Greek journalist who had been writing for the Washington Times when he was detained around June 19, even as the son of a revolutionary icon called for Ahmedinejad's government to be dissolved.

Foreign Ministry spokesman Hasan Qashqavi said that Iason Athanasiadis, believed to be the only journalist held in the widespread crackdown who does not hold Iranian citizenship, had been released in the framework of "Tehran-Athens ties."

There were no details on Athanasiadis' current location.

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The Association of Researchers and Teachers of Qom, Iran's holiest city, questioned whether the Guardian Council, Iran's official electoral watchdog, had enough authority to validate the disputed election results, the Voice of America and the New York Times reported.

"This crack in the clerical establishment, and the fact they are siding with the people and [defeated presidential candidate Mir Hossein] Mousavi, in my view is the most historic crack in the 30 years of the Islamic republic," Abbas Milani, head of the Iranian Studies Program at Stanford University, told the Times.

The group called on other clerics to oppose the election results and Ahmadinejad's government, even calling the estimated 20 people killed in the past three weeks' protests as "martyrs" comparable to the thousands who died during the 1979 Iranian revolution and the 1980-1988 war with Saddam Hussein's Iraq.

Qom, about 100 miles southwest of Tehran, is the spiritual heart of Iranian Shiite Islam and was the power base of the Ayatollah Ruhollah Khomeini, later the leader of the revolution, before he was exiled by the shah in 1964.

Also late Saturday, Mousavi's Web site posted documents it said showed systematic fraud on the part of the Ahmadinejad campaign and the authorities, including the distribution of 20 million extra ballots.

Milani, the Stanford professor, told the Times that he had heard that Mousavi supporter and former President Ali Akbar Hashemi Rafsanjani, one of the most powerful men in Iran, had met with families of those arrested during the post-election crackdown, a sign that Iran's ruling elite was still deeply divided.

Athanasiadis, a freelance reporter, was covering the election and its aftermath when he was detained.

A dual national with both Greek and British citizenship, he is believed to be the only journalist held in the widespread crackdown who does not hold Iranian citizenship.

A Newsweek correspondent, Maziar Bahari, a dual Iranian-Canadian citizen, is also in custody.

Qashqavi said that in the past Athanasiadis had traveled to Iran as a journalist using a British passport, and had been banned from entering the country for "violating the law."

Qashqavi said when Athanasiadis returned on his Greek passport he got involved in "illegal activities" during the post-election unrest and was detained because of "activities contrary to the profession of journalism."

Athanasiadis' parents appealed for his release, calling him a reporter, photographer and filmmaker with a love and respect for Iran.

On Sunday, the son of an Iranian revolutionary icon called on parliament to dismiss Ahmadinejad from his post, as the country's conservative political establishment upped pressure on the reformists.

Ali Reza Beheshti, 47, a close Mousavi ally and son of one of the main leaders of the revolution, urged the parliament to reverse the election results, saying that "people expect their representatives to represent them and not to defend authorities by any means."

"I wish the lawmakers would respect the demands of the majority of their constituents" and submit a bill disqualifying the president, Beheshti was quoted as saying on the pro-Mousavi Web site, Norooznews.

Beheshti, who ran Mousavi's now-banned Kalemeh newspaper, is the younger son of Ayatollah Mohammad Hossein Beheshti, Iran's top judge who was killed in a bombing in 1981.

Iran's leadership has been grappling with how to handle fallout from the elections, which critics maintain Ahmadinejad won by fraud.

On Sunday, the conservative Kayhan newspaper ran its second consecutive editorial targeting Mousavi and his backers, dubbing them as dangerous in comments highlighting the government's predicament.

"How should the Islamic Republic treat such groups? They would be a dangerous opposition if they were to win, and set the streets on fire if they lose," said Sunday's editorial. "The meaning of such behaviors is that they do not accept the system," or Islamic republic.

A day earlier, the paper ran another editorial by Ayatollah Ali Khamenei's top aide that accused Mousavi of being an American agent and suggested he be tried for treason.

Hossein Shariatmadari, a top aide to Khamenei, called for Mousavi and former reformist President Mohammad Khatami to be tried in court for "horrible crimes and treason."

That commentary raised the possibility that Mousavi could be arrested and charged like many other pro-reform figures.

The weeks of unrest that immediately followed the vote have largely died down amid a crackdown by authorities. But reformists have pressed their cause, demanding recounts, appealing to the all-powerful Guardian Council and to the parliament.

The detention of protesters and reports of street violence have further tarnished the image of a government already criticized by many Western nations for a litany of issues — ranging from its controversial nuclear program to its foreign policy in the region.

Iranian officials, however, have resisted calls for a new vote, dismissing allegations of fraud and calling the elections "pure" and "healthy" following the supreme leader's declaration that the results would stand.

They have also said Mousavi's supporters were operating at the behest of foreign powers — namely Britain and the United States.

Officials had detained nine Iranians working at the British Embassy in Tehran, accusing them of fomenting unrest. All but one have been released.

The one still being held, identified by his lawyer as Hossein Rassam, a political analyst at the embassy, was charged with harming Iran's national security, his lawyer, Abdolsamad Khorramshi, said Saturday.

The crackdown has spread to top opposition leaders, as well, with about a dozen detained since the protests began, said lawyer Saleh Nikbakht, who represents a number of them.

The semiofficial news agency Fars reported last week that a prominent reformer, former Vice President Mohammad Ali Abtahi, had "confessed that he has provoked people and students to anarchy and riots and velvet revolution."

Abtahi was a vice president under Khatami. Fars did not give further details about what punishment Abtahi could face or about their confessions.

Their families have rejected the charges as baseless saying confessions obtained under pressure were worthless.

Police say more than a thousand people have been detained in total and 20 "rioters" killed during the violence. Eight members of the paramilitary Basij militia tasked with putting down the protests have also been killed.

Some human rights groups have raised concerns that people detained in the postelection turmoil could be forced into making bogus confessions under torture or other duress.

The Associated Press contributed to this report.