Iran’s U.N. mission in New York did not immediately comment on the report.

The fact-finding team, which was set up at the end of 2022, was refused access to Iran. It said it faced obstacles from government electronic surveillance, harassment and intimidation of some witnesses and victims, deterring many people from giving evidence. But through in-depth interviews with others, along with access to independent reports, medical imaging and official documents, the mission said it was able to collect sufficient evidence to establish facts.

It details patterns of the use of lethal and less lethal force by security forces to disperse protests, including using weapons armed with birdshot and systematically targeting the head, face, neck and genitals of protesters, often inflicting permanent, life-changing injuries.

In their crackdown, the authorities arrested tens of thousands of people, including hundreds of children, some as young as 10, the mission said, noting official statements that the government had pardoned 22,000 people and that the average age of those detained was 15.

But the mission also unveiled evidence of the torture and sexual violence directed at detainees to extract confessions and information and to punish and humiliate the victims. Physical abuse included beating, burning, electric shocks and being held in stress positions. The sexual violence, which investigators said was used against women, men and children, included rape and threats of rape, electrocution of genitals, forced nudity and groping.

Children were held for days, even weeks, without knowing the reasons for their detention and without contact with their families, the investigators reported. “As with adults, they were subjected to severe physical, psychological and sexual torture, including rape.”