Following a wave of mass arrests in response to largely peaceful protests across Iran over the past week, Amnesty International is calling on the Iranian authorities to release any individual held solely for peacefully taking part in them. The authorities must also conduct a prompt, impartial and independent investigation into the killing of a protester in Karaj, north-west of the capital, Tehran, on 3 August 2018. Amnesty International is also urging the authorities to protect all detainees from torture and other ill-treatment and to reveal the fate and whereabouts of dozens of detainees whose families have not heard from them since their arrests.