Iran's state radio said Tuesday that seven people died in clashes in Tehran after an "unauthorized gathering" following a mass rally over alleged election fraud.
The radio report said the seven died in shooting that erupted after several people at the gathering Monday night in western Tehran "tried to attack a military location."
CBS News correspondent Elizabeth Palmer reports, however, that the radio report did not appear to accurately portray the fatal incident. According to CBS News own information gathering, at least six people were shot to death on Sunday night at a massive rally at the University of Tehran.
According to Human Rights Watch, the number of people killed during the rally on Sunday was six, reports Palmer.
The most recent death reported amid the post-election tumult in Iran was a single individual killed late on Monday, just as the day's massive rally was breaking up.
More than 100,000 opponents of President Mahmoud Ahmadinejad marched through Tehran earlier in the day, protesting the alleged vote rigging in last week's elections.
Palmer reports that as the masses were beginning to disperse, a small group of apparent protesters began to attack a local headquarters of Iran's paramilitary force. Video from the scene shows paramilitaries opening fire as the building is torched, under siege from the group. One man was shot and killed in the crowd.
The outpouring in Azadi, or Freedom, Square for reformist leader Mir Hossein Mousavi followed a decision by Iran's most powerful figure for an .
Security forces watched quietly, with shields and batons at their sides.
Later, a group of demonstrators with fuel canisters set a small fire at a compound of a volunteer militia linked to Iran's powerful Revolutionary Guard as the crowd dispersed from the square. As some tried to storm the building, people on the roof could be seen firing directly at the demonstrators at the northern edge of the square, away from the heart of the rally.
An Associated Press photographer saw one person fatally shot and at least two others who appeared to be seriously wounded.
Witnesses told The Associated Press that protests and some violence had broken out in several cities across Iran, including some traditionally seen as more conservative.
President Barack Obama said Iranian voters have a right to feel their ballots mattered and urged the investigation into vote-rigging allegations to go forward without additional violence.
Mr. Obama said reports of violence that followed Iranian elections trouble him and all Americans. He said peaceful dissent should never be subject to violence that followed weekend elections that gave President Mahmoud Ahmadinejad a second term.
"It would be wrong for me to be silent on what we've seen on the television the last few days," Mr. Obama told reporters at the White House.
Gary Sick, a former White House advisor on Iran who is still considered one of the world's foremost experts on the country, told CBS News the election results showed total contempt for the voters.
"They announced the election far earlier than they could possibly have known what the outcome really was," Sick said. "The numbers don't add up."
"We're talking tens of millions of people voting, and they had the votes counted and announced within practically no time at all after the polls closed... Even if you had the best voting machines in the world, and they don't," Sick added. "Most of this is paper ballots, how do you count 30 million paper ballots in an hour or two?"
The chanting demonstrators had defied an Interior Ministry ban and streamed into central Tehran - an outpouring for Mousavi that swelled as more poured from buildings and side streets.
The crowd - many wearing the trademark green color of Mousavi's campaign - was more than five miles long, and based on previous demonstrations in the square and surrounding streets, its size was estimated to be in the hundreds of thousands.
As his 4-wheel-drive inched through the mob, he tried to address them on a loudspeaker, reports Palmer.
Mousavi (at left) said his solution was "canceling the result of this disputed election."
"This will have the least cost for our nation. Otherwise, nothing will remain of people's trust in the government and ruling system."
The crowd roared back: "Long live Mousavi."
Riot police watched, but seemed to have instructions not to interfere; that's a dramatic turnaround from the past two days - when they attacked and beat any opposition demonstrators brave enough to take to the streets, reports Palmer.
They also targeted journalists: CBS News' cameraman had to stay hidden behind a storefront grill to avoid arrest.
One placard said, in English: "This is not election. This is selection." Other marchers held signs proclaiming "We want our vote!" and they raised their fingers in a V-for-victory salute.
"We want our president, not the one who was forced on us," said 28-year-old Sara, who gave only her first name because she feared reprisal from authorities.
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," Sick 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 points 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 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 says 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.