Hundreds of pro-cleric militants and security forces clashed with Iranians throughout the capital late Friday, firing machine guns in the air and using tear gas and batons to put down any public opposition to the country's hard-line regime.
The clashes were the most intense and widespread of four consecutive nights of clashes in Tehran (search), which were sparked by university students and snowballed into broader displays of opposition to Iran's clerical establishment.
Unlike previous nights, no protests against supreme leader Ayatollah Ali Khamenei (search) were seen, making it unclear what sparked Friday night's clashes involving hundreds of militants — some in groups of two to four, others on motorcycles — who beat pedestrians with batons, brandished knifes or hurled rocks at crowds and homes.
Protesters had been calling for an end to the country's hard-line establishment and for supreme leader Khamenei's death. Criticism of Khamenei is usually punished by imprisonment, and public calls for his death had been unheard of until this week.
Khamenei's hard-line supporters — who control key government institutions in Iran — are locked in a power struggle with popularly elected President Mohammad Khatami (search), who came to power aiming to reform Iran's conservative political system.
During the past few nights, the largest crowds of protesters and onlookers were concentrated around the Tehran University compound in the capital's Amirabad district, the scene of many of the clashes between students and security forces.
Hundreds of police had locked down the area earlier in the day, lining streets to prevent people from gathering and stopping suspect cars for spot searches.
Late Friday night, packs of militants — often backed by security forces — rushed onlookers, beating them with batons and their fists in order to break up the crowds. Some of the militants were seen riding motorcycles and chasing pedestrians.
The charred wreck of at least one the militant's motorcycle, apparently burned by ordinary Iranians, was seen lying in a street nearby the university.
Witnesses said security officers fired machine guns in the air and tear gas at crowds to disperse hundreds of onlookers in a residential area about one mile from the dormitory.
Two women aged in their 50s denounced the hard-line militants, with one telling The Associated Press, "The days of these bearded vigilantes are coming to an end."
The women, who declined to be identified, said they saw the militants throwing stones at people's homes and smashing windows.
The militants — often referred to as vigilantes — pledge loyalty to Khamenei and his hard-line clerics and act voluntarily to break up protests without government approval.
Although the protesters criticize the clerics, public support for Khatami also appears to be falling because of his government's inability to implement promised reforms.
During a Friday prayer sermon at Tehran University, former president Hashemi Rafsanjani (search) — a key Khamenei supporter — urged Iran's youth not to fall into what he described as a U.S. trap by denouncing the country's political leadership.
"I advise the youth, especially students ... that they should be careful not to fall into trap dug out by the Americans," Rafsanjani told worshippers.
Rafsanjani said it was Iran's policy to "act resolutely" to prevent demonstrations from getting out of hand but "not to be harsh on protesters."
While the recent protests seemed to be disorganized, with no clear leaders, some demonstrators vowed to keep up the pressure until next month's anniversary of the much larger and violent protests in 1999.
Khamenei this week warned of a major crackdown in a speech broadcast on state television and radio. He referred to violence in 1999, when security forces and extremist supporters of hard-line clerics attacked pro-democracy demonstrators after a student dormitory was stormed.
The dormitory raid led to the death of at least one student and generated the worst street battles since the 1979 Islamic Revolution.
Exiled opposition groups have been encouraging dissent in Iran through U.S.-based Persian language TV channels. U.S. pressure on Iran, which Washington accuses of hiding a nuclear weapons program and harboring terrorists, may have further emboldened those who hope to see the regime toppled.