TEHRAN, (Reuters) – Five people died in Tehran yesterday when pro-reform protesters clashed with security forces,  police said, in the worst outbreak of violence since June’s  contested presidential election sparked political turmoil.

Opposition websites said eight people were killed in Tehran  and other cities across Iran when tens of thousands took to the  streets during a religious festival. Police in the capital said  they were investigating the “suspicious” deaths, the IRNA news  agency reported.

Among the dead was opposition leader Mirhossein Mousavi’s  nephew. State TV said “unknown assailants” killed Ali Habibi  Mousavi Khamene, whose death was described as a “martyrdom” by a  Mousavi ally.

It is the first time people have died in street protests  since the immediate aftermath of the June presidential election  in which the opposition says more than 70 people were killed.

The authorities have estimated the post-vote death toll at  about half that number, including pro-government militiamen.

Opposition website Jaras said police shot and killed four  protesters in central Tehran. State TV dismissed foreign media  reports that security forces had killed protesters. It said  police had fired into the air to disperse demonstrators.

Jaras said clashes continued in Tehran on Sunday night and  police fired tear gas to disperse protesters in some squares.

“More protesters have gathered near Tajrish square in the  past few minutes … Police have increased their violence after  more people gathered … near the state-run radio and television  building,” Jaras said.

“Police have not been able to disperse protesters despite  using tear gas,” it said in a report that could not be  independently verified.  Foreign media have been banned from  reporting directly from opposition protests since the June  election.

A journalist for Dubai TV went missing yesterday in Tehran,  a source at the television station said.

More than 300 protesters were arrested in Tehran during the  day, state TV said, adding that several banks, bus stops and  trash cans were set on fire during the protests.

“Dozens of police officers have been injured including  Tehran’s police chief,” Iran’s deputy police chief Ahmadreza  Radan told state TV. “One person fell from a bridge, two died in  car accidents and one was shot dead, but not by police.”

Last evening, opposition supporters in northern Tehran  chanted Allahu Akbar (God is Greatest) from rooftops, as they  did in the months after the election. Shots were heard in the  area.

Jaras said unrest spread to other parts of Iran, including  the holy city of Qom. Clashes erupted in the cities of Shiraz,  Isfahan, Najafabad, Mashhad and Babol, it said,

“We will kill those who killed our brothers,” Jaras quoted  demonstrators as chanting.

“DECEIVED HOOLIGANS”

The White House condemned what it called the “unjust  suppression” of civilians by the Iranian government and said the  United States was on the side of protesters.

“Hope and history are on the side of those who peacefully  seek their universal rights, and so is the United States,” White  House National Security Council spokesman Mike Hammer said.

France condemned “the arbitrary arrests and violence  committed against protesters”.

Iranian authorities had warned the opposition against using  the two-day Shi’ite Muslim Tasoua and Ashura festival on Dec.  26-27 to revive protests against the clerical establishment.

“The Iranian nation has shown tolerance so far but they  should know that the … system’s patience has a limit,” Mojtaba  Zolnour, a representative of Supreme Leader Ayatollah Ali  Khamenei in the Revolutionary Guards, said, the semi-official  Fars News Agency reported.

It said Mousavi’s supporters “followed the call of the  foreign media” and took to the streets — a reference to the  government position that the unrest is being stoked by foreign  enemies of the Islamic Republic.

It said the group of “deceived hooligans” damaged public and  private property and “disrespected” the holy Shi’ite day of  Ashura, without elaborating.

Jaras website said at least four protesters were killed and  many others wounded in the city of Tabriz, a Mousavi stronghold.  A witness in Tabriz told Reuters that people poured into the  streets, chanting anti-government slogans.

Photographs from the clashes showed one man whose face was  covered in blood, lying on the ground. Other pictures showed  burning motorbikes and protesters throwing stones at police.

This year’s Ashura coincided with the seventh day of  mourning for leading dissident cleric Grand Ayatollah Hossein Ali Montazeri, who died a week ago at the age of 87 in Qom.

A spiritual patron of Mousavi’s movement, he was a fierce  critic of the hardline clerical establishment.

Baton-wielding riot police also fired tear gas and warning  shots to disperse Mousavi supporters on Saturday, Jaras reported.

Despite scores of arrests and security crackdowns,  opposition protests have flared repeatedly since the poll, which  the opposition says was rigged to secure President Mahmoud  Ahmadinejad’s re-election. The authorities deny the claim.

The election turmoil has complicated the international  dispute over Iran’s nuclear programme, which the West believes  may have military ends, not just civilian purposes.