Tehran - Police and protestors criticizing Iranian President Mahmoud Ahmadinejad's government clashed Wednesday in Tehran as demonstrators shouted slogans such as "Death to the dictator" and authorities responded with tear gas, witnesses said. Former parliament speaker Mehdi Karroubi, one of the leaders of the opposition, was seen at the protest, but the moderate cleric had to leave the scene after he was attacked by pro-Ahmadinejad supporters, said witnesses, who added several protestors had been arrested.
Some reformist websites reported police firing at protestors, but witnesses said they saw police firing into the air and could not verify the website reports.
The witnesses put the number of protestors into the thousands and said they had gathered in several parts of downtown Tehran.
The clashes between the demonstrators and police occurred on a square near the US embassy, where the main state-organized anti-US rally was held Wednesday in observance of the Day of National Confrontation against World Imperialism.
The day is marked on November 4 every year - the anniversary of the 1979 seizure of the US embassy in Iran by Islamist students in support of the Iranian Revolution - with government-organized rallies across the nation.
Supporters of the opposition - mainly members of the Green Movement, which backs opposition leader and this year's failed presidential candidate Mir-Hossein Moussavi - were also using the 30th anniversary to protest against Ahmadinejad.
Because of restrictions put in place in June, the foreign media was once again prohibited from covering the demonstrations and allowed only to report from the state-organized anti-US ceremony.
The foreign media had to rely on reports from witnesses and opposition groups for news of the opposition rally.
The official IRNA news agency, however, confirmed the opposition gathering and theanti-Ahmadinejad slogans but said the demonstrators numbered 200.
Moussavi and former president Mohammad Khatami were due to attend Wednesday's protests, but there were no reports of their arrival.
Iranian police and security were deployed a large numbers in downtown Tehran ahead of the anti-government protests.
Volunteer pro-Ahmadinejad militia forces joined the government forces in deploying in alleys to confront the anti-government protestors.
Almost all streets leading to Tehran's downtown were blocked because of heavy traffic and several parts of the capital had virtually come to a standstill.
Many shops in the affected districts had eitherclosed or had no customers.
Opposition protests began after Ahmadinejad was declared the winner of the presidential election in June amid charges of fraud from his opponents. The demonstrations led to the arrest of 4,000 opposition supporters, of whom more than 100, including former reformist officials, remained in jail on charges of planning to topple the Islamic system.
Estimates of the death toll from the earlier demonstrations vary from 30 to 79 with no official confirmation on any casualty figures.
The opposition is led by the quartet of Moussavi, Karroubi, Khatami and another former president, Akbar Hashemi-Rafsanjani.