Amnesty International has revised its estimated death toll from the unrest that rocked more than 100 Iranian towns and cities last week to 161, from an earlier toll of 143.
"The confirmed number of protesters killed in Iran has risen to at least 161 protesters, according to credible reports received by Amnesty International," it said in a brief statement sent to RFE/RL on November 29.
The London-based human rights watchdog added that "the real death toll is likely to be significantly higher than this."
The extent of the crackdown against the days of protests over fuel-price hikes remains unclear, mainly due to a near-total Internet blackout imposed by the authorities for several days.
Authorities have yet to publish any definitive official death toll for the unrest that broke out on the evening of November 15 and saw protesters attack police stations, torch gasoline pumps, and loot shops.
In a report published on November 27, Human Rights Watch (HRW) accused Iranian authorities of "deliberately covering up" the extent of the repressive measures taken against those who took part.
Video footage posted on social media "clearly shows security forces using firearms targeting protesters," the report said.
Iranian lawmaker Hossein Naghavi Hosseini, who sits on the parliament’s National Security and Foreign Policy Committee, was quoted as saying more than 7,000 people were arrested.
Iran's clerical establishment has blamed the unrest on "thugs" backed by its foreign foes, including the United States and its allies Israel and Saudi Arabia.