An Iranian opposition website said three protesters were "killed" when police opened fire in Tehran on Sunday in a second day of violence during a Shi'ite Muslim religious mourning ritual, but the capital's police chief denied the report.
The clashes on Sunday came as the country's Shia Muslim's marked Ashoura, a religious event commemorating the 7th century death of Prophet Muhammad's grandson.
The Jaras website, in reports that could not immediately be independently verified, later said another protester was killed in clashes between opposition supporters and security forces in the capital, without giving details.
"Protesters chanted anti-government slogans when carrying his body," Jaras said, adding fierce clashes also erupted in the central cities of Isfahan and Najafabad.
"Three people were killed and two others were wounded when police opened fire at protesters," Jaras said about the situation in downtown Tehran.
Shooting was also heard elsewhere in a central area of the capital, it said.
The same website earlier said security forces fired tear gas to disperse opposition supporters in Tehran.
It said protesters set one police motorbike on fire. A plume of black smoke could be seen above the centre of the city, Jaras added, as police blocked streets in the area and clashes intensified.
A witness told Reuters there was a heavy presence of both security forces and opposition backers in central Tehran, a city of around 12 million people.
"Police prevented groups of protesters from joining each other," she said.
Other witnesses said thousands of pro-government Iranians were also gathering in central Tehran.
A mobile phone network appeared to be down, Tehran residents said.
The authorities have warned the opposition against using a two-day Shi'ite Muslim religious mourning ritual on Dec. 26-27 to revive protests against the government.
Meanwhile, a senior Iranian police official denied a report on an opposition website that four protesters were killed during clashes in Tehran on Sunday, the Students News Agency ISNA reported.
"So far there have been no reports of killings and no one has been killed up to now," Tehran police chief Azizollah Rajabzadeh said, quoted by ISNA.
There was no immediate official comment on the reports.
Last Mod: 27 Aralık 2009, 17:07
Foreign media have been banned from reporting directly from opposition demonstrations after a disputed presidential election in June.
The official IRNA news agency said two women and a child were hurt when rioters threw stones at people marking Ashura.
The semi-official Fars News Agency said supporters of opposition leader Mousavi "followed the call of the foreign media" and took to the streets.
It said the group of deceived hooligans damaged public and private property and disrespected the holy Shi'ite day of Ashura, without elaborating.