The wife of Iranian opposition leader Mir Hossein Mousavi said Thursday that her brother is among the hundreds arrested in Iran's postelection crackdown, and she warned authorities not to publish any "forced confessions" from him or other detainees.

More than 500 people remain imprisoned after the heavy crackdown against protests that erupted in support of Mousavi after the disputed June 12 election. Among them are many top politicians from pro-reform political parties, human rights lawyers, journalists and activists.

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Some hard-line officials have claimed that detainees have confessed to being in the service of "foreign enemies" to fuel the protests as part of a "soft revolution" against the government. The opposition denies the accusations and says any confessions have been obtained under torture or duress.

Mousavi's wife, Zahra Rahnavard, told the semiofficial ILNA news agency that her 62-year-old brother was arrested more than a month ago. "We have tried all legal and peaceful means to try to win the release of him and other detainees," Rahnavard said, adding that she was speaking out now because some officials have spoken of allegations against her brother.

She said her brother, Shahpour Kazemi, a communications engineer, was "apolitical" and that "accusations of provoking riots or connections to foreigners ... are unimaginable."

She warned those that are making accusations against detainees that "a divine anger will catch them and the nation will reject them."

Rahnavard, a former dean of Tehran's al-Zahra University, campaigned alongside her husband in the election, a rarity for a candidate's wife, which made her a star among women and student supporters. Her original name is Zohreh Kazemi but she changed it in the 1960s when she became an activist against the U.S.-backed shah, and she was a prominent activist in the 1979 revolution that brought the Islamic Republic to power.

This week, the political chief of the elite Revolutionary Guards, Yadollah Javan, issued a public call for authorities to make public any confessions to prove to Iranians that the opposition protests were foreign-inspired.

Mousavi claims to have won the presidential election and that President Mahmoud Ahmadinejad's victory was fraudulent. Hundreds of thousands of supporters marched in the streets in the weeks after the elections, until the crackdown by police, Revolutionary Guards and Basiji militiamen. At least 20 people were killed in the crackdown — though human rights groups say the number is likely far higher.

Mousavi on Wednesday said he intends to soon issue a document for moving ahead with the opposition campaign that he said would "go beyond" forming a political front or party, as some aides have said he will do. He said the document would have a plan for "activating neglected parts of the constitution," according to opposition Web sites.

He did not elaborate, but warned that the situation in Iran was "heading in the direction of becoming more militarized," a reference to the increasing power of security forces in the postelection crackdown. He repeated his stance that Ahmadinejad's government "does not have the support of people's vote and therefore does not have legitimacy."

On Thursday, members of the pro-government Basij militia arrested the father of a 27-year-old who was killed during a June 20 protest, the pro-Mousavi Norooz news Web site reported. Basijis arrested the father of Masou Hashemzadeh from his Tehran home and collected black signs of mourning at the house's entrance, it said. Pro-reform Web sites have reported that families of slain protesters have been intimidated not to mourn publicly.