TEHRAN, Iran (CNN)  -- Iran's supreme leader on Friday rejected opposition claims that last week's presidential elections were rigged, describing President Mahmoud Ahmadinejad's win as "definitive" and demanding an end to days of protests.



Ayatollah Ali Khamenei made his first address since the June 12 presidential elections.



In his first speech since the June 12 election outcome sparked the country's worst unrest in 30 years, Ayatollah Ali Khamenei said the vote accurately reflected the will of the people and accused "enemies of Islam" of stoking anger.



He warned opposition leaders, who are planning a new rally on Saturday, against staging further demonstrations, saying they would be held accountable for any violence.



The "Islamic establishment would never manipulate votes and commit treason. The legal structure in this country does not allow vote-rigging," Khamenei said, in his first address since the elections.



He told a large crowd at Tehran University that the "historic" 85 percent turnout of more than 40 million people was a "political earthquake" and was too large to have been manipulated.



"There is a difference of 11 million votes. How can vote-rigging happen?" he added.  Watch Khamenei dismiss claims of fraud »



Ahmadinejad, whose hardline policies have antagonized Western nations, claimed victory with more than 62 percent of the votes, surprising many experts who had predicted a stronger showing from main opposition leader Mir Hossein Moussavi.



The Ayatollah's speech was likely to come under heavy scrutiny in Iran, amid expectations that, despite conciliatory comments, his strong endorsement of Ahmadinejad will do little to appease Moussavi's emboldened supporters.  Read about Iran's power structure »



Moussavi's allegations of ballot fraud and calls for a fresh vote have rallied thousands on the streets of Tehran and other cities, in scenes not witnesses in country since the Islamic Revolution of 1979 toppled its monarchy.



The unrest prompted Iran to place restrictions on foreign media, limiting their reports on six days of street protests, police arrests and some outbreaks of violence that have left at least eight people dead. Watch militia crackdown »



Khamenei described the dispute over the election outcome as a disagreement within Iran's establishment, accusing "foreign enemies" and "Zionists" -- including the United States, Britain and Israel -- of fomenting violence, and criticizing international media coverage of the unrest.



Britain's Foreign Office confirmed shortly after the speech that it was summoning Iran's London ambassador in response to Khamenei's comments.



His speech was punctuated with exhortations from the crowd, including: "Allah is Great," "Death to Israel," "Death to America," and "Death to Britain."



Expressing support for Ahmadinejad, Khamenei accused rival election candidates of insulting the president in the run-up to the vote.



"They swore and called the president superstitious and called him names, which is embarrassing. They forgot about morality and law," he said.



Khamenei, who has authorized a partial vote recount, said proper legal channels should be used for any challenge to the election outcome. He called for an end to street protests, warning that perpetrators of violence would face punishment.



On Thursday, tens of thousands of demonstrators took to the streets of Iran's capital for the sixth day in a row. Some estimates put the total number of participants in the hundreds of thousands. See where protests have taken place »



Moussavi spoke through a bullhorn from atop a building to the throngs of marchers who snaked through the city, in what was described as a peaceful protest.



He spoke hours after the Iranian government agreed to meet with candidates for crisis talks to discuss complaints stemming from the election.



With restrictions on reporting the unrest, much of the news, video and images emerging from Iran have come via social networking sites, often bypassing authorities' attempts to block applications such as Facebook and Twitter.



CNN's Chief International Correspondent Christiane Amanpour described Khamenei's address as a heartfelt defense of Iran's establishment but said it was uncertain the opposition would heed his call to end demonstrations.  Watch Amanpour discuss speech. »
Who is Khamenei? Who rejects claims of ballot rigging? Who is Iran's supreme leader? What sparked unrest? What is his name? What is he criticizing? What sort of protests?
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