July 9 (Bloomberg) -- Police fired tear gas as thousands of protesters defied a ban on a march toward Tehran University to mark unrest during student protests in 1999, Agence France- Presse said, citing witnesses.

Demonstrators chanted “Death to the dictator” as they gathered in the streets around the university, the center of the protests 10 years ago, AFP said. Police fired two volleys of tear gas, the newswire said.

The demonstration came after hundreds of thousands of people took to the streets last month to protest the June 12 re- election of President Mahmoud Ahmadinejad. The opposition said the vote was rigged, a charge denied by the president. Authorities used force against the demonstrators, and as many as 20 people were killed, according to state-run media. Le Figaro this week cited hospital staff as saying at least 92 died.

“If some people make moves that are contrary to security plans under the influence of anti-revolutionary networks, they will be crushed under the feet of our alert people,” Tehran Governor Morteza Tamaddon warned late yesterday, the state-run Islamic Republic News Agency reported. During the incident 10 years ago, militiamen attacked dormitories at the university after students protested the closure of a newspaper.

To contact the reporter on this story: Ali Sheikholeslami in London at alis2@bloomberg.net.

Last Updated: July 9, 2009 11:08 EDT