June 16: Supporters of Mir Hossein Mousavi run in the street during protests in Tehran after the nation banned foreign media from covering rallies.
June 16: Thousands of people attend a state-organized rally in a square in central Tehran, Iran.
June 15: Fire burns at a Basij militia base after a rally in support of former presidential candidate Mirhossein Mousavi in western Tehran.
June 15: Supporters of Mir Hossein Mousavi march through Tehran in a protest against election results that gave Mahmoud Ahmadinejad the victory.
June 14: Iranian supporters of presidential candidate Mir Hossein Mousavi are followed by Iranian riot police in front of Tehran University.
June 14: Iranian President Mahmoud Ahmadinejad, gestures, during a news conference.
June 13: Supporters of Iran's reformist presidential candidate are chased by security forces as they pass by a burning bus on the streets of Tehran.
June 12: Iranian men line up to get ballots for the presidential elections at a polling station in Tehran, Iran.
Iranian opposition leader Mir Hossein Mousavi issued a direct challenge Wednesday to the country's supreme leader and cleric-led system, calling for a mass rally to protest disputed election results and violence against his followers.
A crackdown on dissent continued, with more arrests of opposition figures reported, and the country's most powerful military force — the Revolutionary Guard — saying that Iranian Web sites and bloggers must remove any materials that "create tension" or face legal action.
In one high-profile display of apparent opposition support, several Iranian soccer players wore green wrist bands — the color of Mousavi's campaign — during a World Cup qualifying match in South Korea that was televised in Iran.
Supreme Leader Ayatollah Ali Khamenei has told Mousavi to pursue his demands through the electoral system and called for Iranians to unite behind their Islamic government, an extraordinary appeal in response to tensions over the presidential vote. But Mousavi appears unwilling to back down, issuing on his Web site a call for a mass demonstration Thursday.
"We want a peaceful rally to protest the unhealthy trend of the election and realize our goal of annulling the results," Mousavi said.
He called for his followers to wear or carry black in mourning for the alleged election fraud and the deaths of protesters, and said there should be "a new presidential election that will not repeat the shameful fraud from the previous election."
Web sites associated with Mousavi and the reformists called for at least one rally later Wednesday but the opposition leader made no reference to the gathering in his official statement.
Mousavi and his supporters accuse the government of rigging the June 12 election to declare hard-line President Mahmoud Ahmadinejad the overwhelming winner. Their street protests, paired with dissent from powerful clerical and political figures, have presented one of the gravest threats to Iran's complex blend of democracy and religious authority since the system emerged from the 1979 Islamic Revolution.
Election tensions appeared to be spreading further into the Iranian political and religious classes — and into the sports world.
Mousavi's Web site said seven Iranian players wore the green bands on their wrists in the first half of the World Cup qualifier, although most were forced to take them off in the second half. Mehdi Mehdavi-Kia kept his green band on throughout the game, which Iran and South Korea drew 1-1.
Fans from Iran unfurled a banner in the stands that read "Go To Hell Dictator," and waved Iran's national flags emblazoned with the plea "Free Iran."
Blogs and Web sites such as Facebook and Twitter have been vital conduits for Iranians to inform the world about protests and violence.
The Web became more essential after the government barred foreign media Tuesday from leaving their offices to report on demonstrations on the streets of Tehran.
Mousavi condemned the government for blocking Web sites, saying the government did not tolerate the voice of the opposition.
The violence has left at least seven people dead, according to Iran's state media, although videos and photos posted by people inside Iran show scenes of violence that have not been reported through official channels. The newly imposed media restrictions make it virtually impossible to independently verify much of the information, which includes dramatic images of street clashes and wounded demonstrators.
Much of the imagery has been posted anonymously. In other cases, those who have posted have declined to be identified due to fear of government retaliation, or cannot be reached due to government restrictions on the Internet and mobile phones.
The Revolutionary Guard, an elite military force answering to Khamenei, said through the state news service that its investigators have taken action against "deviant news sites" that encouraged public disturbances. The Guard is a separate military with enormous domestic influence and control of Iran's most important defense programs. It is one of the key sources of power for the ruling establishment.
The statement alleged that dissident Web sites were backed by Canadian, U.S. and British interests, a frequent charge levied by hard-liners against the opposition.
"Legal action will be very strong and call on them to remove such materials," it said.
The semiofficial ISNA news agency and the private ILNA news agency reported that scuffles broke out between two legislators — one a reformist and the other a hard-liner — in an open session of parliament after they argued about the election.
The agencies said hard-liner Ruhollah Jani Abbaspour attacked reformer Amir Taherkhani after a parliamentary committee probing the protests met Mousavi and the speaker of parliament gave a report on the inquiry.
Mousavi has also sought support from Iran's grand ayatollahs — widely respected clerics at the top of the religious hierarchy, although most don't have direct political roles. He sent a letter to one liberal grand ayatollah, Yousef Sanei, who was encouraging, issuing a statement calling for "achieving rights and respect for the people's votes."
Iran's most senior dissident cleric, Grand Ayatollah Hossein Ali Montazeri, said widespread vote fraud had undermined the legitimacy of the ruling Islamic system and that "no sound mind" would accept the results.
"A government that is based on intervening in (people's) vote has no political or religious legitimacy," said Montazeri, who had once been set to succeed Ayatollah Ruhollah Khomeini as supreme leader until he was ousted because of criticisms of the revolution.
State media said Khamenei would deliver the sermon at Friday prayers, the most important religious address of the week. The supreme leader generally leads Friday prayers only two or three times a year.
Unlike past student-led demonstrations against the Islamic establishment, Mousavi has the ability to press his case with Iran's highest authorities and could gain powerful allies. Some influential clerics have expressed concern about possible election irregularities, and a fierce critic of Ahmadinejad, former President Hashemi Rafsanjani, is part of the ruling establishment.
Rafsanjani, who was president from 1989-97, also heads the Assembly of Experts, one of the cleric-run bodies that is empowered to choose or dismiss Iran's supreme leader. Khamenei is Khomeini's successor, and the assembly has never used its power to remove Iran's highest authority.
Iranian TV showed pictures of Faezeh Hashemi, Rafsanjani's daughter, speaking to hundreds of Mousavi supporters, carrying pictures of Khomeini and others.
The U.S.-based International Campaign for Human Rights in Iran said that several dozen noted figures associated with the reform movement have been arrested, among them politicians, intellectuals, activists and journalists.
Tehran-based analyst Saeed Leilaz, who is often quoted by Western media, was arrested Wednesday by plainclothes security officers who came to his home, said his wife, Sepehrnaz Panahi.
At least 10 Iranian journalists have been arrested since the election, Reporters Without Borders said, and a Web site run by former Vice President Mohammad Ali Abtahi said the reformist had been arrested.
Prominent reformer Saeed Hajjarian has also been detained, Hajjarian's wife, Vajiheh Masousi, told The Associated Press. Hajjarian is a close aide to former President Mohammad Khatami.
To try to placate the opposition, the main electoral authority has said it was prepared to conduct a limited recount of ballots at sites where candidates claim irregularities. The recount would be overseen by the Guardian Council, an unelected body of 12 clerics and Islamic law experts close to Khamenei.
Mousavi charges the Guardian Council is not neutral and has already indicated it supports Ahmadinejad. He and the two other candidates who ran against Ahmadinejad are calling for an independent investigation.
His representative, reformist cleric Ali Akbar Mohtashamipour, said after a meeting with the council Tuesday the number of votes in counted in 70 districts was higher than the population in those districts. He also said many polling stations were closed sooner than scheduled on election night while people were still lining up.
On Tuesday, the government organized a large rally in Tehran to show it too can bring supporters into the streets. Speakers urged Iranians to accept the election results.
The appeal for unity failed to calm passions, and a large column of Mousavi supporters marched peacefully in north Tehran, according to amateur video.
A witness told the AP that the pro-Mousavi rally stretched more than a mile (1.5 kilometers). Security forces did not interfere, the witness said, speaking on condition of anonymity for fear of government reprisal.
Ahmadinejad, who has dismissed the unrest as little more than "passions after a soccer match," attended a summit Tuesday in Russia that was delayed a day by the unrest. He returned to Iran and held a cabinet meeting, saying on state television Wednesday that people had voted for his "policies of justice."
In Washington, President Barack Obama expressed "deep concerns" about the legitimacy of the election and post-voting crackdowns.