TEHRAN (Reuters) – Iranian police detained at least 15 people and used tear gas and batons to disperse supporters of opposition leader Mirhossein Mousavi outside Tehran University on Friday, a witness said. The incident took place as former President Akbar Hashemi Rafsanjani led Friday prayers inside the university grounds. Mousavi supporters outside chanted slogans calling for the release of people detained since last month’s disputed presidential election and for the resignation of President Mahmoud Ahmadinejad when police moved to disperse them, the witness said.