Rights group calls 'alarming' death toll 'evidence that Iran's security forces went on a horrific killing spree'.
Iranians are protesting against a rise in government-set petrol prices.
Tehran shut-down the internet during the anti-government demonstrations.
Iranian state TV admits security forces shot and killed 'rioters' in Tehran, Shiraz and Sirjan.
Al Jazeera's Assed Baig reports live in the Iranian capital Tehran.