Anti-government student protesters in Iran say they have been badly injured in violent clashes during four days of unrest in the capital, Tehran.
Hundreds of hard-line vigilantes wielding sticks and iron bars chased and beat demonstrators outside Tehran University Friday night. Gunshots also echoed in the area as Islamic militants sped around on motorbikes trying to silence protests against Iran's supreme leader, Ayatollah Ali Khamenei.
On the campus, students report dozens of vigilantes stormed at least two dormitories, beating up some students in their beds and detaining several others. A student spokesman said more than 50 students were injured in the attacks and some two dozen have disappeared.
Observers say Friday's protests were the most widespread and violent of four consecutive days of demonstrations against Iran's clerical rule. It was also the first time in recent days police stood by and allowed Islamic militants to take part in the tough clampdown.
Diplomats in Tehran say the Iranian government wants to send a clear message that the protests have crossed their line of tolerance.
Security forces fired machine guns into the air and used tear gas and batons to put down the opposition.
The demonstrations have been directed against both Iran's pro-reform President Mohamed Khatami, and hard-line clerics who have blocked his attempts to bring about social and political change.
Ayatollah Ali Khamenei has accused the United States of fomenting the unrest. It is believed that U.S. based, opposition-run Persian satellite television channels are promoting the protests.
At Friday prayers at Tehran University, former president Hashemi Rafsanjani, a key supporter of Ayatollah Khamenei, called on Iranian youth not to fall into what he described as a U.S. trap by denouncing the country's leadership.
But some demonstrators have vowed to keep the pressure up until next month's anniversary of the much larger and more violent protests in 1999.
U.S. officials are also maintaining their own pressure on Iran. They accuse the Islamic republic of interfering in Iraq, developing weapons of mass destruction and harboring terrorist fugitives, charges Iran denies.