Protests broke out across Iran in mid-November after the government announced it was raising fuel prices and rationing fuel amid a deep economic crisis triggered by US sanctions.
Dozens of deaths were recorded in Shahriar city in Tehran province, one of the cities with the highest death toll, Amnesty wrote.
Families of victims have been threatened and warned against speaking to the media or holding funerals, and in some cases, bodies have only been released to families in exchange for extortionate payments, according to information gathered by Amnesty.
The human rights organization called on the international community to act, writing, "those responsible for the bloody clampdown on the demonstrations must be held accountable for their actions."
"This alarming death toll is further evidence that Iran's security forces went on a horrific killing spree, that left at least 208 people dead in less than a week," said Philip Luther, research and advocacy director for the Middle East and North Africa at Amnesty International.
"This shocking death toll displays the Iranian authorities' shameful disregard for human life," he added.
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