Article published on the 2009-12-27 Latest update 2009-12-27 13:02 TU
Three protesters were shot dead by security forces on Engelhab Street, central Tehran, according to the opposition site Rahesabz, which says that another two were injured.
Ths site says that a fourth protester was killed further down the street.
But police deny that any protesters have been killed.
"So far police have not received any reports of people killed and nobodyhas been killed," Tehran Metropolitan Police Chief Azizollah Rajabzadeh told the Iran Students' News Agency. "Police have not opened fire in Tehran and the policemen on duty did not carry any assault weapons."
Rajabzadeh confirmed that there had been arrests but could give no figure for how many.
Thousands of opposition supporters have launched new protests as Iran's majority Shia-Muslims mark Ashura, the annual rituals in honour of the death of the Imam Ali.
They follow demonstrations after the death of dissident cleric Grand Ayatollah Hossein Ali Montazeri and protests in the aftermath of this year's presidential election.
President Mahmoud Ahmadinejad attended an officially organised Ashura ceremony.