Pro-government and pro-opposition students staged rival rallies at a Tehran university on Tuesday, the official IRNA news agency reported, in a sign of continuing tension after clashes during protests last week.
IRNA said about 700 pro-government students gathered at a Tehran branch of Azad University protesting against an "insult" to the Islamic Republic's late founder, Ayatollah Ruhollah Khomeini, during opposition demonstrations on Dec. 7.
They chanted slogans, including "Death to America."
About 100 pro-reform students gathered nearby, chanting slogans against the opposing side, IRNA said. There were no immediate reports on the rallies on reformist websites.
Tension has increased in Iran since student backers of opposition leader Mirhossein Mousavi clashed last week in Tehran with police armed with batons and tear gas in the largest such protests over June's disputed presidential election in months.
State television has broadcast footage of what it said were opposition supporters tearing up and trampling on a picture of Khomeini during the rallies, when pro-reform students sought to renew their challenge to hardline President Mahmoud Ahmadinejad.
The opposition has denied involvement in the reported incident, suggesting the authorities were planning to use it as a pretext for a renewed post-election crackdown on dissent.
Security forces have repeatedly warned that any "illegal" gathering would be firmly confronted.
More radical mood
"If you do not confront these (opposition groups), the people will come to the scene and uproot the sources of this movement and this plot," said Gholamreza Shafizadeh, a regional representative of Supreme Leader Ayatollah Ali Khamenei.
The presidential election plunged Iran into its deepest internal crisis since the overthrow of the U.S.-backed Shah three decades ago and exposed deepening establishment divisions.
The authorities have rejected opposition charges of vote fraud and portrayed huge pro-Mousavi protests that erupted after the poll as a foreign-backed bid to undermine the Islamic state.
Last week's protests were much smaller than those in the days after the vote. But the mood seemed more radical with demonstrators chanting slogans against the clerical establishment and not just criticizing Ahmadinejad's victory.
Reformist websites have reported about continued small, pro-Mousavi protests at several universities over the last week.
Crowds of clerics and other leadership loyalists have staged many pro-government rallies in recent days to condemn the "insult" toward Khomeini, according to official media.
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