Verified videos emerging from Iran show bodies piled up in a hospital, snipers stationed on buildings and CCTV cameras being destroyed, following the unprecedented crackdown on protests earlier this month.
BBC Verify has been tracking the spread of protests across Iran since they first erupted in late December, but the near total internet blackout imposed by the authorities has made it extremely difficult to document the scale of the state's deadly crackdown on protesters.
The US-based Human Rights Activists News Agency (HRANA) says it has confirmed the killing of nearly 6,000 people, including 5,633 protesters, since the unrest began at the end of December. It says it is also currently investigating another 17,000 reported deaths received despite an internet shutdown after nearly three weeks.
Another group, the Norway-based Iran Human Rights (IHR), has warned that the final toll could exceed 25,000.
Iranian authorities said last week that more than 3,100 people were killed, but that the majority were security personnel or bystanders attacked by "rioters".
