TEHRAN (Reuters) -- An "illegal splinter group" of an Iranian student body caused damage and clashed with security personnel during a gathering at Iran's largest university on December 7, the official IRNA news agency reported.
Pictures obtained by Reuters showed hundreds of people gathered at Tehran University in the center of the Iranian capital, some of them carrying pro-democracy banners.
One photograph showed some demonstrators tearing down a metal gate at the university, one of the oldest campuses in Iran. IRNA called those who gathered a "limited group" and said they had attacked the university's western entrance gate.
Student protests have been relatively rare in recent years in Iran, which is embroiled in a nuclear row with the United States and is often criticized by Western rights groups for cracking down on dissent at home.
Liberal-minded students and academics have criticized President Mahmud Ahmadinejad for clamping down on dissent on campuses. The president and his government say they support free speech and welcome constructive opposition. Ahmadinejad is expected to seek another four-year term in an election in June.
"We want democracy," said a placard carried by one protester on one of the photographs made available to Reuters. "Return expelled students and professors," said another.
IRNA said people gathering at the campus "must have confused Tehran University with a battlefield" and denounced their "savage moves and insulting slogans."
Referring to a prominent Iranian student movement, the state news agency said that "an illegal splinter group associated to the Office of Consolidation of Unity tried to express their existence by inflicting damage to the university's property."
It did not give details about the damage at the university.
Students and activists say some of those who have spoken out against the conservative government have been detained or blacklisted from university courses.
Rights activists say other dissenting voices, including labour movement figures and women's rights campaigners, have also been targets of a government crackdown.
[The events coincided with the annual Students Day
, an anniversary that has proven a rallying point for students critical of Iran's theocratic leadership.]