TEHRAN - Police fired teargas on Monday to disperse supporters of reformist leader Mirhossein Mousavi who gathered to express their condolences over his nephew's death in an anti-government rally, an Iranian opposition website said.
Iran's Supreme National Security Council said eight people were killed on Sunday in anti-government protests across Iran that erupted during the religious festival of Ashura. Iran's Health Ministry said over 60 people had been injured in Tehran.
The deaths and scale of confrontations may signal a volatile new phase in which security forces loyal to Supreme Leader Ayatollah Ali Khamenei try to crush the reformist movement.
"These are the hardest clashes we've seen since June," said a Western diplomat in Tehran, referring to demonstrations after the disputed presidential election, adding that bitterness over the deaths may spark fresh protests and a harsh state reaction.
He said Iran's leadership was under great pressure but showed no sign of losing its grip.
Among the dead on Sunday was a nephew of Mousavi. State television said unknown assailants killed Ali Habibi Mousavi Khamene. A Mousavi ally described his death as martyrdom.
"A group of Mousavi supporters have gathered in front of Ebn- e Sina hospital where his nephew's body was kept ... Police fired teargas to disperse them," the Norooz website reported.
A moderate website said on Monday the body of Mousavi's nephew was missing from the hospital.
"We can not hold a funeral until my brother's body is found," said another of Mousavi's nephews said, according to parlemannews. Clashes were expected at the funeral ceremony.
Violence flares up
Violence flared up across Iran. Jaras opposition website said three advisers of Mousavi were detained on Monday, a day after five people were killed in Tehran. Earlier the website reported the arrests of four pro-reform politicians.
Opposition websites said police fired on protesters in Tehran on Sunday, saying eight people were killed in the capital and other cities when tens of thousands of people took to the streets. Police denied the claim.
Police said the "suspicious deaths" were under investigation and that 300 protesters had been arrested, adding dozens of security men had been injured in the running street clashes.
The Intelligence Ministry said members of an exiled opposition group, the Mujahideen Khalq Organization, were among those arrested.
Another opposition leader Mehdi Karoubi accused Iran's hardline rulers on Monday of killing innocent people, Jaras reported.
Police had earlier reported five dead in violence in Tehran, the first such fatalities since the street protests immediately after June's presidential election.
"What has happened to this religious system that it orders the killing of innocent people during the holy day of Ashura?" asked moderate cleric Karoubi, who came fourth in the election, in a statement posted on Jaras.
Opposition politician arrested
Jaras said opposition politician Ebrahim Yazdi, leader of the banned Freedom Movement and foreign minister in Iran's first government after the 1979 Islamic revolution that overthrew the U.S.-backed shah, was detained early on Monday at his home.
Jaras said police shot dead four protesters in central Tehran on Sunday and that unrest had also erupted in the cities of Qom, Shiraz, Isfahan, Najafabad, Mashhad and Babol.
The reports could not be independently verified because foreign media are banned from directly covering protests.
Tabriz prosecutor Yahya Mirzamohammadi denied a Jaras report that four protesters had been killed in the northwestern city. He told the ISNA news agency no protests had occurred there.
The United States condemned Iran's "unjust suppression" of civilians and said it was on the side of protesters.
A hardline clerical group in the holy city of Qom condemned the "sedition by rioters" during the Shi'ite Muslim religious ritual of Ashura, the official IRNA news agency said.
"The association of Qom theologians ... asks officials to identify those behind yesterday's events and take appropriate measures to firmly encounter and punish them according to legal and religious standards," it said in a statement.
Political turmoil has convulsed Iran since the re-election of hardline President Mahmoud Ahmadinejad in a vote his opponents said was fraudulent, a charge the authorities deny.
Demonstrations have persisted, now increasingly on important days in the Islamic Republic's religious and political calendar, as the opposition seeks to sustain its own momentum.
Heavy security measures eventually quelled the first explosion of mass protests that plunged Iran into its biggest internal crisis since the 1979 Islamic revolution.
The opposition says more than 70 people were killed in the early protests. Officials say the toll -- including members of a pro-government Islamic militia -- was less than half that.
The unrest, which has divided the political and clerical elite, has also complicated Iran's decision-making in the long-running dispute over its nuclear program, which the West fears is a cover to build bombs. Tehran denies this.