A human rights watchdog accused Iran’s intelligence and security forces on Thursday of torturing children arrested as part of the brutal crackdown on the country’s anti-regime protests.

Amnesty International said in a report that children as young as 12 were subjected to “beatings, flogging, electric shocks, rape and other sexual violence” while in detention.

The report’s release marks six months since a popular uprising erupted in Iran after the suspicious death in custody of 22-year-old Mahsa Amini, following her arrest for violating the Islamic Republic’s dress code for women. Iranian authorities have responded to the protests with a violent crackdown, killing hundreds of protesters while detaining thousands of others. They also handed death sentences to at least 109 protesters, according to the Oslo-based Iran Human Rights group. Four men are known to have been executed so far on charges related to civil unrest.

Iranian authorities have acknowledged the arrest of more than 22,000 people involved in the protests. State media outlets reported that many of those arrested were children. Based on the testimonies of dozens of detainees across the country, Amnesty International estimates that thousands of children are currently in detention.