TEHRAN (Reuters) -- An ally of Iranian opposition leader Mir Hossein Musavi has been detained, a reformist website says, the third pro-reform opponent of President Mahmud Ahmadinejad to be held within the past week.
The Etemad-e Melli website said Mohammad Ozlati-Moghaddam, a member of Musavi's campaign headquarters staff ahead of the disputed June election, was detained in his home earlier this week after it was searched.
It did not give a source for the report and there was no immediate comment from Iranian officials.
Reformist websites reported the detentions of senior moderates Alireza Hosseini Beheshti and Morteza Alviri on September 8. Beheshti's office, which looked into the situation for postelection detainees and the number of deaths in street unrest after the vote, was also raided.
On September 9, Musavi urged his supporters not to be provoked by the detentions, saying they were a "sign of more horrendous events to come."
Musavi and pro-reform cleric Mehdi Karrubi, who finished second and fourth respectively, say the poll was rigged to secure Ahmadinejad's reelection. Officials reject the charge.
The hard-line president shored up his position last week when parliament approved most of his new ministers after almost three months of political turmoil in the major oil exporter.
Karrubi, whose newspaper was closed down three weeks ago, angered hard-liners in August by saying some jailed protesters were raped and abused in jail. Authorities denied it, while the judiciary and parliament have agreed to look into the issue.
Etemad-e Melli is the website of Karrubi's party.
It also carried a letter by Karrubi to the head of the judiciary, in which he said the Revolutionary Guard had ordered the Health Ministry not to release information about people wounded in postelection unrest.
The Guards and a pro-government Islamic militia helped quell the huge opposition protests that followed the election.
Their influence appears to have grown since Ahmadinejad, himself a former Guardsman, came to power in 2005. A senior Guards commander last month called for the arrest of Musavi and Karrubi.
In his letter, Karrubi "disclosed new dimensions in regards to investigations on postelection crimes," Etemad-e Melli said.
"Don't let armed and paramilitary forces, after commanding the field of politics and medicine, begin thinking about intervening in judicial affairs and add another summit to their postelection conquests," Karrubi's letter said.
The election and its turbulent aftermath plunged Iran into deep internal crisis. Rights groups say thousands of people, including senior pro-reform figures, were arrested after the poll, though most have been freed.
The opposition says more than 70 people were killed in the unrest. Officials estimate the death toll at up to 36 people and say members of the Islamic Basij militia were among them.
Hard-liners have portrayed the opposition protests as a foreign-backed bid to undermine the Islamic government system.