Violence and tensions continued to flare in Tehran on Sunday as President Mahmoud Ahmadinejad defended his re-election as "real and free" while his closest rival launched a formal appeal of the voting results.

"The election was a real and free one. The election will improve the nation's power and its future," Ahmadinejad told a news conference made up of Iranian and foreign media.

Calling the vote an "epic moment," he pointed out that "40 million people have taken part in this process. How can they question it?"

Clashes between police and anti-Ahmadinejad protesters broke out after election results showed a nearly two-to-one landslide for Ahmadinejad over his nearest rival, Mir Hossein Mousavi.

According to government officials, Ahmadinejad won 62.6 per cent of the vote, while Mousavi garnered 33.75 per cent in a contest that appeared to divide urban and rural voters.

Mousavi filed an appeal Sunday with Iran's Guardian Council, which is made up of a group of clerics.

"Fraud is evident and review and nullification is requested," said the letter posted on Mousavi's website.

Mousavi also met with Iran's supreme leader Ayatollah Ali Khamenei to discuss his fraud allegations.

Meanwhile, there were reports of more protests and demonstrations in Tehran and elsewhere in the country, the CBC's Nahlah Ayed reported.

According to some reports, as many as 100 reform group members had been arrested.

"There is a very heavy police presence in the streets," Ayed reported from Tehran.

"It is really tense," she said, adding that "everyone says they have really never seen anything like this before."

Global reaction

Thousands of people in other countries, including Canada, the United States and Germany, took to the streets to express their frustration. In Berlin, protesters marched to the Iranian Embassy.

Hundreds of Iranian-Canadians rallied in several cities, including Toronto, Ottawa and Edmonton, on Sunday.

Germany's foreign minister Frank-Walter Steinmeier denounced the violence in Iran and expressed concern about voting "irregularities."

U.S. Vice-President Joe Biden, mindful of President Barack Obama's attempts to reach out to Iran, was more circumspect.

"I have doubts, but we're going to withhold comment until we have a thorough review of the whole process and how they react in the aftermath," he said.

In the voting, Ahmadinejad maintained broad support among rural and working-poor voters, while Mousavi took much of the middle-class and urban vote.

Also on Sunday, Ahmadinejad appeared at a victory rally in the capital, waving and smiling as a huge crowd — which Ayed reported contained "thousands and thousands" — waved banners and cheered.

With files from The Associated Press