Iranian security forces armed with batons and tear gas clashed with supporters of the late dissident cleric Grand Ayatollah Hossein Ali Montazeri in two cities yesterday, opposition websites said.

But a senior local official denied reports of clashes in Isfahan, accusing foreign media of "staging a psychological war" against the clerical establishment by publishing such reports.

"A small group of people who gathered in Isfahan were dispersed by ordinary Iranians. Security forces did not clash with people," said Mohammad Mehdi Esmaili, deputy governor of Isfahan province, the official Irna news agency reported.

One opposition website said tear gas and pepper gas were used against people gathering for a Montazeri memorial service planned in a mosque in the city of Isfahan, while another said women and children were among those beaten up.

Some opposition supporters were injured and dozens were arrested, according to reformist websites, whose reports could not be independently verified.

If confirmed, they further highlight mounting tension in the major oil producer, six months after a disputed presidential election plunged the Islamic Republic into its deepest internal crisis since it was founded three decades ago.

Police chief Esmail Ahmadi-Moqadam warned the pro-reform opposition of "fierce" confrontation if it continued its "illegal" activities, the semi-official Fars news agency said.

Reformist former president Mohammad Khatami condemned the violence in Isfahan, the reformist Parlemannews website said.

"Imam Khomeini (Iran's revolutionary leader) believed that the Islamic Republic was based on two pillars - freedom and independence. If these pillars become shaky... we will have tyranny again," Mr Khatami said.

The Jaras website said many demonstrators were hurt during the clashes in Isfahan on the traditional third day of mourning for Montazeri, who died on Saturday aged 87 in the holy Shi'ite Muslim city of Qom.

"Police fired tear gas to disperse people... many people were injured... some arrested," Jaras said.