Iranian opposition groups say security forces armed with tear gas and batons have clashed with supporters of a late dissident cleric as they rallied in central Iran.
Opposition Web sites say police cracked down Wednesday on gatherings in memory of Grand Ayatollah Hossein Ali Montazeri in Isfahan and his birthplace of Najafabad.
Reportssay security forces in Isfahan fired tear gas and used batons to disperse demonstrators who shouted pro-reform slogans, arresting more than 50 of them and injuring many others. Amateur video that could not be independently verified appears to confirm the accounts of violence.
Opposition groups say Iranian police also clashed in Najafabad with reformists who chanted anti-government slogans.
Iran has banned foreign media from covering protests directly.
Earlier, Iranian police official Esmail Ahmedi-Moghadam told journalists the opposition must "stop its illegal activities" or police would stop them.
Ayatollah Montazeri died Sunday in Qom at the age of 87.
He was considered a spiritual patron of Iran's reformist movement and a strong critic of the nation's conservative clerical establishment.
Opposition groups said hundreds of thousands of mourners joined a funeral procession for the ayatollah in Qom Monday that evolved into a major anti-government protest. Government supporters in Qom staged a smaller counter demonstration on Tuesday.
Opposition Web sites said security forces in Isfahan surrounded the house of a leading reformist cleric, Ayatollah Jalaleddin Taheri, who had called on people to attend Wednesday's memorial for the late cleric.