Tens of thousands of supporters of defeated Iranian presidential
candidate Mir Hossein Mousavi have heeded his call to gather and mourn
those who have died in post-election violence.
Mr. Mousavi joined the demonstrators Thursday at Tehran's Imam Khomeini square. Most in the crowd were dressed in black, in accordance with Mr. Mousavi's directions to wear the color of mourning, rather than his campaign color green which has become a symbol of the protests.
At least seven protesters were killed by pro-government militia in Tehran on Monday.
There have been daily mass demonstrations since Iranian authorities declared the June 12 election victory of incumbent President Mahmoud Ahmadinejad with 63 percent of the vote. Mr. Mousavi wants the vote annulled and held again.
Iran's Council of Guardians, a powerful body that supervises the elections, has invited Mr. Mousavi and two other defeated presidential candidates to a meeting Saturday to discuss their concerns.
The council has offered to conduct a partial recount of the vote, and a spokesman for the body says it has begun examining a total of 646 complaints of irregularities.
The unrest over the election results is the worst in Iran since its 1979 Islamic revolution.
Iran's authorities are trying to block foreign media coverage of the demonstrations, so news organizations have relied heavily on accounts and images sent by Iranian citizens using social media networks including Twitter, Facebook and YouTube.
The government has also conducted widespread arrests of opposition members, including politicians, activists and journalists since the beginning of the week.
Included in the roundup, is Saeed Laylaz, a prominent economist and journalist who has been critical of Mr. Ahmadinejad's policies.
Former Foreign Minister Ebrahim Yazdi was arrested while at a hospital Wednesday, according to his Freedom Movement Party.
Mohamad Atrianfar, an editor of a number of newspapers has also been detained.
Iran's Fars News agency quotes Iranian Intelligence Minister Gholam Hossein Mohseni Ejehi saying the ministry has arrested more than 30 people it says were "leaders and planners" of post-election unrest. The report does not identify any of the detainees by name.
The intelligence ministry also said Thursday it had uncovered a terrorist plot to plant bombs at public places and mosques during the election. The ministry says it has arrested several suspects allegedly linked to foreigners.
Fars also reports authorities have barred the daughter and son of former President Akbar Hashemi Rafsanjani from leaving the country. The agency did not give the source for its information.
Iranian TV had broadcast images Wednesday of Mr. Rafsanjani's daughter, Faezeh, speaking to a crowd of opposition supporters this week.
During the presidential campaign, Mr. Ahmadinejad accused the Rafsanjani family of corruption, fueling a rivalry between the two politicians.
Iran's Supreme Leader, Ayatollah Ali Khamenei, has called for national unity and is due to lead Friday prayers in Tehran. The occasion is expected to be used as a show of strength for President Ahmadinejad's supporters.