Iranian police fired tear gas and beat anti-government protesters with batons to disperse thousands at a graveside memorial Thursday for victims of post-election violence, witnesses and state television said.

Police barred opposition leader Mir Hossein Mousavi from joining the crowd around the grave of Neda Agha Soltan, a young woman was shot to death at a June 20 to protest the disputed presidential election. The 27-year-old music student's dying moments on the pavement were filmed and circulated widely on the Web, and her name became a rallying cry for the opposition.

"Neda is alive, Ahmadinejad is dead," some of those at the ceremony chanted, referring to President Mahmoud Ahmadinejad, who the opposition claims won the June 12 election by fraud. Witnesses said plainclothes forces charged at them with batons and tear gas, some of them chanting, "Death to those who are against the supreme leader." State television also reported that police used tear gas to disperse the demonstrators.

Soltan's mother, Hajar Soltan, told the British Broadcasting Corp. on Thursday she is waiting for Neda's killer to be arrested and brought to justice.

"Her death has been so painful. Words can never describe my true feelings. But knowing that the world cried for her, that has comforted me. I am proud of her. The world sees her as a symbol and that makes me happy," she said.