Violence erupts in second day of protest in Tehran

Protesters set fires and smashed shop windows in a second day of violence as groups challenging President Mahmoud Ahmadinejad's re-election tried to keep pressure on authorities.

The Iranian government has responded with anti-riot squads and blackouts of web networks used to rally the pro-reform campaign.

Mr Ahmadinejad dismissed the unrest - the worst in the decade in Tehran - as "not important" and insisted the results showing his landslide victory on Friday were fair and legitimate. A huge rally in his support was organised even as clashes flared around the capital.

The violence spilling from the disputed results has pushed Iran's Islamic establishment to respond with sweeping measures that include deploying anti-riot squads around the capital and cutting mobile phone messaging and internet sites used by the campaign of Mr Ahmadinejad's election rival, Mir Hossein Mousavi.

There is little chance that the youth-driven movement could immediately threaten the pillars of power in Iran - the ruling clerics and the vast network of military and intelligence forces at their command - but it raises the possibility that a sustained and growing backlash could complicate Iran's policies at a pivotal time.

President Barack Obama has offered to open dialogue after a nearly 30-year diplomatic freeze. Iran also is under growing pressure to make concessions on its nuclear program or face possible more international sanctions.

In Paris, French Foreign Minister Bernard Kouchner said he was "very worried" about the crackdown on protesters.

"France regrets that instead of openness, there has been quite a brutal response. ... This will leave its mark, and the opposition will organise itself."

So far, Mr Mousavi has issued mixed signals through his website before it was shut down. He urged for calm but also said he is the legitimate winner of Friday's election and called on supporters to reject a government of "lies and dictatorship".

He has not been seen in public since a news conference shortly after polls closed.

In a second day of clashes, scores of young people shouted "death to the dictator" and broke the windows of city buses on several streets in central Tehran. They have burned banks, trash bins and piles of tires used as flaming barricades to block police.

Riot police beat some of the protesters with batons while dozens of others holding shields and motorcycles stood guard nearby. Shops, government offices and businesses closed early as tension mounted.

Along Tehran's Vali Asr Street - where pro-Mousavi activists held a huge pre-election rally last week - tens of thousands of people marched in support of Mr Ahmadinejad, waving Iranian flags and shouting his name.

In a news conference, Mr Ahmadinejad called the level of violence "not important from my point of view" and likened it to the intensity after a soccer match.

"Some believed they would win, and then they got angry," he said. "It has no legal credibility. It is like the passions after a football match. ... The margin between my votes and the others is too much and no one can question it."

About a mile away from Mr Ahmadinejad's news conference, young Iranians set bins, banks and tires on fire as riot police beat them back with batons.

"In Iran, the election was a real and free one," said Mr Ahmadinejad. "The election will improve the nation's power and its future," he told a packed room of Iranian and foreign media.

Mr Ahmadinejad also accused foreign media of launching a "psychological war" against the country.

Iranian authorities have asked some foreign journalists - in Iran to cover the elections - to prepare to leave. Nabil Khatib, executive news editor for Dubai-based news network Al Arabiya, said the station's correspondent in Tehran was given a verbal order from Iranian authorities that the office will be closed for one week.

About a dozen riot police used batons to disperse about 50 Mousavi supporters standing outside his campaign quarters.

On Saturday, Mr Mousavi, a 67-year-old former prime minister, released a web message saying he would not "surrender to this manipulation."

Authorities responded with targeted detentions, apparently designed to rattle the leadership of Mousavi's "green" movement - the trademark colour of his campaign.

The detentions include the brother of former reformist President Mohammad Khatami and two top organisers of Iran's largest reformist party, the Islamic Iran Participation Front: the party's secretary-general and the head of Mousavi's youth cyber campaign. Mohammad Reza Khatami and the two party activists were released Sunday.

Several others linked to Mr Mousavi's campaign remained in custody, but the full extent of the arrests were not known.

Iran's supreme leader, Ayatollah Ali Khamenei, closed the door for possible compromise. He could have used his near-limitless powers to intervene in the election dispute. But, in a message on state TV on Saturday, he urged the nation to unite behind Mr Ahmadinejad, calling the result a "divine assessment."

The US has refused to accept Mr Ahmadinejad's claim of a landslide re-election victory said it was looking into allegations of election fraud. There are no independent election monitors in Iran.

US Secretary of State Hillary Rodham Clinton said she hoped the outcome reflects the "genuine will and desire" of Iranian voters.

The European Union also said it was "concerned about alleged irregularities" during Friday's vote.

In Beirut, Lebanon's militant Hezbollah group - which is aided by Iran - congratulated Mr Ahmadinejad and said the vote was conducted in an atmosphere of "freedom".