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Clashes in the Iranian capital left seven people dead during an "unauthorized gathering" at a mass rally over alleged election fraud — the first official confirmation of deaths linked to the wave of protests and street battles that have erupted after disputed elections last week.

Iranian state radio reported that the deaths occurred after protesters "tried to attack a military location." It gave no further details, but it was a clear reference to crowds who came under gunfire Monday after trying to storm a compound for volunteer militia linked to Iran's powerful Revolutionary Guard.

The shootings came at the end of huge rally by opponents of President Mahmoud Ahmadinejad claiming widespread fraud in Friday's voting. The protest movement has shown no signs of easing — with another reported rally planned for later Tuesday — and has even forced Iran's non-elected ruling clerics into the unfamiliar role of middlemen between the government and its opponents.

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The deaths also raise the prospect of further defiance and anger from crowds claiming that reformist leader Mir Hossein Mousavi was the rightful winner of the election. On Tuesday, thousands of people waving Iranian flags and pictures of the supreme leader gathered at a rally organized by Iran's clerical regime in an apparent attempt to reclaim the streets hours after saying it would recount disputed presidential ballots.

"This nation will protect and defend its revolution in any way," Gholam Ali Haddad Adel, a prominent lawmaker and Ahmadinejad supporter, said as the crowd in Vali Asr square pumped their fists in the air and cheered in support, images on state-run television showed.

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Also Tuesday, Iranian authorities restricted all journalists working for foreign media from reporting on the streets.

The rules cover all journalists, including Iranians working for foreign media. It blocks images and eyewitness descriptions of the protests and violence that has followed last week's hotly-disputed elections.

The order limits journalists for foreign media to work only from their offices, conducting telephone interviews and monitoring official sources such as state television.

The deaths Monday occurred on the edge of Tehran's Azadi (Freedom)Square after hundreds of thousands of Mousavi supporters defied an official ban and marched through the city. An Associated Press photographer saw gunmen, standing on a roof, opening fire on a group of demonstrators who tried to storm the militia compound.

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Angry men showed their bloody palms after cradling the dead and wounded who had been part of a crowd that stretched more than five miles.

The march also marked Mousavi's first public appearance since shortly after the election and said he was willing to "pay any price" in his demands to overturn the election results.

Ahmadinejad, meanwhile, arrived in Russia on Tuesday to attend a regional security summit, after having postponed the trip for one day.

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Supreme Leader Ayatollah Ali Khamenei said Monday that the government would conduct an investigation into the election. The move seemed intended to calm protester anger but was followed by a rally of hundreds of thousands of people that presented one of the greatest challenges to Iran's government since it took power in the 1979 Islamic Revolution.

Iran's state radio said seven people were killed in clashes from that protest — the first official confirmation of deaths linked to the street battles following the disputed election.

Witnesses saw people firing from the roof of a building used by a state-backed militia after some Mousavi supporters set fire to the building and tried to storm it.

Mousavi supporters had called for demonstrations Tuesday but Mousavi said in a message in his Web site he would not be attending any rally and asked his supporters to "not fall in the trap of street riots" and "exercise self-restraint."

Ahmadinejad traveled to Russia Tuesday after delaying a trip for a day but did not mention the Iranian election or unrest. Instead, he focused on the traditional target of the Islamic Republic's ire, the United States.

"America is enveloped in economic and political crises, and there is no hope for their resolution," he said through an interpreter. "Allies of the United States are not capable of easing these crises."

A Web site run by Iran's former reformist vice president, Mohammad Ali Abtahi, said he had been arrested by security officers, but provided no further details. Abtahi's Web site, popular among the youth, has reported extensively on the alleged vote fraud after Friday's election.

In Washington, President Obama said he believes the ayatollah's decision to order an investigation "indicates he understands the Iranian people have deep concerns."

But at the same time, Obama said it would not be helpful if the United States was seen by the world as "meddling" in the issue.

The president did say, however, that he worries "when I see violence directed at peaceful protesters, when I see peaceful protest being suppressed."

The death toll reported Tuesday was the first in Tehran since the postelection turmoil gripped Iran and could be a further rallying point in a culture that venerates martyrs and often marks their death with memorials. One of Mousavi's Web sites said a student protester was killed early Monday in clashes with plainclothes hard-liners in Shiraz in southern Iran but there was no independent confirmation of the report.

Britain and Germany joined the calls of alarm over the rising confrontations in Iran. In Paris, the Foreign Ministry summoned the Iranian ambassador to discuss the allegations of vote-tampering and the violence.