TEHRAN, Iran (CNN)  -- Iran's election authority has rejected claims of voting irregularities by a defeated presidential candidate, while acknowledging that the number of ballots cast in dozens of cities exceeded the number of eligible voters there, state-run TV reported Monday.



Protesters face Iranian riot police on a street in Tehran on Saturday.



Iran's Guardian Council -- which approves all candidates running for office and verifies election results -- said candidate Mohsen Rezaie alleged irregularities in 170 cities, and that excessive ballots were found in 50 cities, according to government-funded Press TV.



Council spokesman Abbas-Ali Kadkhodaei said voting in those locations did not noticeably affect the outcome of the election, adding that the council will continue to investigate complaints that are filed through "legal channels," Press TV said. The council declared President Mahmoud Ahmadinejad the winner of the June 12 election.



Rezaie had reported some irregularities and called for a recount of some ballots, while opposition leader Mir Hossein Moussavi and candidate Mehdi Karrubi have rejected the election as fraudulent and demanded a new one.



Earlier Sunday, thousands of riot police and militia lined Tehran's streets as the public rift among Iranian leaders appeared to be widening.



The country's foreign minister disputed allegations of ballot irregularities in Iran's disputed presidential election, and the parliamentary speaker implied the nation's election authorities had sided with one candidate.



Amateur video showed large crowds marching down a major Tehran thoroughfare shouting, "Don't be afraid, we're together!" and "Death to dictator!" The person who shot the video said it was taken Sunday, but CNN could not immediately verify that the protest had taken place.



Eyewitnesses reported a protest also took place at southern Tehran's Azad University, where final exams were postponed after about 200 students refused to take them.



Thousands of riot police and members of the Basij militia lined the streets of the city, according to eyewitnesses. Security personnel surrounded the headquarters of the country's state television and radio. Many shops were closed, and shopkeepers whose stores were open said they planned to close early Sunday. However, no tanks were seen on the city's streets. Traffic was light.  Watch amateur video of a volunteer paramilitary forces headquarters burning in Tehran »



A statement purportedly from Moussavi on Sunday called on Iranians to "exercise self control" during protests in Tehran, while still supporting their right to demonstrate against the government and the results of the disputed June 12 presidential election.



"The country belongs to you. The revolution and the system is your heritage," the statement attributed to Moussavi said in a statement posted on his Web site. "Protesting against lies and cheating is your right. Be hopeful about regaining your rights. Do not allow anyone who tries to make you lose hope and frighten you make you lose your temper."



The authenticity of the message could not be verified; it was posted in Farsi and translated by CNN.



The message came a day after hospital sources said 19 people were killed in clashes between anti-government protesters and police. Unconfirmed reports put the death toll as high as 150.  See images of the clashes Saturday »



"The sad news of the martyrdom of another group who protested the results of the elections has caused our society astonishment and our people mourn them," said the statement attributed to Moussavi. "Firing on people, militarization of the city's atmosphere, threats, agitations and show of force are all the illegitimate children of law breaking and we are facing all of that. It is a wonder that the perpetrators accuse others of breaking the law for expressing their opinions."  Watch how social-networking sites spread the word on Iranian news »



Police have not been given permission to use firearms in confronting protesters, Tehran Police Chief Azizollah Rajabpour told Iran's semi-official Mehr news agency. Police have not used firearms on the public, he said. Allegations to the contrary are false and "spread by those who want to muddy the waters," the agency reported.



News coverage in Iran has been limited by government restrictions on international journalists. On
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