The human rights organisation Amnesty International on Sunday condemned reports of excessive violence by Iranian security forces against people protesting the results of Friday elections and called for an investigation.
"The shocking scenes of violence meted out by the security forces need to be urgently investigated and those responsible for human rights violations must be brought to justice," said Hassiba Hadj, an AI official, in a statement e-mailed to DPA in Washington.
Hadj is deputy director of the Middle East and North Africa programme of the London-headquartered organisation.
Amnesty International said that at least 170 people were arrested on Saturday as supporters of Iran's opposition leader Mir-Hossein Moussavi protested the results that declared President Mahmoud Ahmadinejad re-elected by a 62 per cent majority.
Iranian police said 60 people had been arrested as some protestors threw rocks at store windows and carried out other acts of violence.
Amnesty International said it had reports that plain-clothes security forces used batons to beat and disperse many non-violent individuals, causing many injuries.
The report cited several incidents, saying University of Tehran students had reportedly been chased by 100 riot police. It said police on motorcycles had beat Moussavi supporters who were staging a peaceful sit-in in Tehran's Vanak Square.
According to the rights organization, protests had spread to other cities including Rasht, Mashahd, Shiraz, Ahwaz, Zahedan and Oroumiye.
"We deplore that the new presidential term is heralded with widespread abuses," the group said. "Amnesty International considers anyone arrested simply for demanding transparency and for questioning the results of the election is to be a prisoner of conscience who should be immediately and unconditionally released."