A new demonstration at Tehran University on Sunday, damaging the main gate to allow outsiders into the campus and denouncing President Mahmoud Ahmadinejad, news agencies reported.

The protesters chanted slogans against the president and carried banners calling for the release of three fellow students who have been held since May in a high-profile case, the Fars news agency state-run IRNA reported.

Arabshahi said the protest lasted for more than two hours after starting at 12:00 pm (0830 GMT) and that it was peaceful.

"We are gathered here to say students are alive and are critical of wrong polices," IRNA quoted another unnamed student as saying.

The demonstration came a day after the intelligence ministry said it had arrested an unspecified number of people using "fake student cards to hold an illegal demonstration" at Tehran University.

The timing of those arrests was not given, but it is likely that they took place before Friday which was annual students' day in Iran