Last Updated 10:16 a.m. ET
Iran's reformist leader Mir Hossein Mousavi urged his supporters to "not fall in the trap of street riots" and "exercise self-restraint" a day after election protests turned deadly in Tehran.
Thousands of people gathered Tuesday in a state-organized rally that Iran's state media said was designed to demand punishment for the rioters from Monday's clashes.
While there had been reports earlier of another rally Tuesday of supporters of reformist challenger Mir Hossein Mousavi, possibly setting the stage for violent clashes, Moussavi, in a message posted on his Web site, said he would not be attending any rally. Mousavi and his supporters claim President Mahmoud Ahmadinejad's reported election victory is fraudulent.
Hundreds of thousands of supporters took to Tehran's streets Monday for a largely peaceful rally in the city's Freedom Square. But the dramatic protests ended violently after pro-government militia members fired into a crowd of demonstrators after some reportedly tried to storm a government compound.
At least one died in the shooting and Iran's state radio said during the clashes - the first official confirmation of deaths linked to the wave of protests and street battles following the disputed election.
After images were shown around the world of the protests and violence, the government on Tuesday cracked down on journalists.
Authorities restricted journalists, including Iranians working for foreign media from reporting on the streets, and said they could only work from their offices, conducting telephone interviews and monitoring official sources such as state television.
The rules prevent media outlets from sending independent photos or video of street protests or rallies.
Also Tuesday, foreign reporters in Iran to cover last week's elections began leaving the country. Iranian officials said they will not extend their visas.
Meanwhile, Iran's Islamic leadership is prepared to of disputed presidential elections, a spokesman said Tuesday, as thousands of people took to the streets to show support for the regime and authorities cracked down on independent media.
According to Iran's state-controlled media, the council, which controls nearly every aspect of life and law in the country, said that if they find evidence of fake identity cards being used or votes being bought, they will order a recount in those areas.
State TV quoted council spokesman Abbas Ali Kadkhodaei as saying that the recount would be limited to voting sites where candidates claim irregularities took place. It was not clear which or how many voting sites would be affected.
CBS News correspondent Elizabeth Palmer reports that it is hard to envision limited recounts in some areas having a significant effect on the total tally as it stands - a purported landslide victory for Ahmadinejad.
The 12-member Guardian Council, made up of clerics and experts in Islamic law and closely allied to Khamenei, must certify ballot results and has the apparent authority to nullify an election. But it would be an unprecedented step. Claims of voting irregularities went to the council after Ahmadinejad's upset victory in 2005, but there was no official word on the outcome of the inquiry, and the vote stood.
"It's a little difficult to imagine that they're going to do a good job, because the Council of Guardians is the organization that basically disqualifies anybody they don't like from the election," Gary Sick, a former White House advisor on Iran who is still considered one of the world's foremost experts on the country, explained to CBS News. "They have a history of taking a partisan position, so it's difficult to see them doing a serious investigation."
Sick pointed out, however, that given the furor generated by these election results and the fierce opposition from within the country, "there are a lot of people looking over their shoulders, and it may be harder to run a cover-up than it had appeared on the surface."
More likely, the dramatic intervention by Khamenei and the Guardian Council could buy time in hopes of reducing the anti-Ahmadinejad anger. The prospect of spiraling protests and clashes is the ultimate nightmare for the Islamic establishment, which could be forced into back-and-forth confrontations and risks having the dissidents move past the elected officials and directly target the ruling theocracy.
Sick told CBS News that Iran's regime may be finding it harder to "cover up" the purported election fraud than they expected.
"They anticipated that there would be an outburst of opposition, they would crack down hard - which they have done - people would back away and be intimidated and that would end it in a day or so. It hasn't worked that way," added Sick.
© 2009 CBS Interactive Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.