Police and elite Revolutionary Guards have warned the opposition to avoid using a Student Day state rally to revive anti-government protests. The opposition was warned that any "illegal" rally will be fiercely confronted.
"Police are using batons to disperse demonstrators. People are chanting anti-government slogans in the Ferdowsi square," said the witness.
Reuters was unable to verify the clash report independently because Iran has banned foreign media reporters from leaving their offices from December7 to December 9.
Iran is commemorating on Monday the killing of three students in 1953 under the former Shah.
Some reformist websites called on people to gather near Tehran University campus, where the main state rally will take place.
Another witnesses said riot police had surrounded Tehran University to prevent the opposition from hijacking the state rally.
(Editing by David Stamp)
