Islamic militants in Iraq have created slave markets, trading and selling women and children of Christian and Yazidi groups, according to UN investigators.
At least 2,500 women and children have been imprisoned, sexually abused and sold for around $10 each by Isis slavers.
The slave markets in the al-Quds area of Mosul in Iraq and Raqqa in Syria have been used as a way of attracting new recruits to Islamic State, the UN said according to a Times report.
Women who were captured at the end of August managed to contact the UN, having kept hold of their mobile phones. They reported being subject to sexual assaults.
The UN study is based on claims made in 450 interviews with Iraqi witnesses to alleged war crimes.
UN high commissioner for human rRights Zeid Ra'ad al Hussein told the Daily Mail: "The array of violations and abuses perpetrated by ISIL and associated armed groups is staggering, and many of their acts may amount to war crimes or crimes against humanity."
One 13-year-old Yazidi girl gave a harrowing account of what happened to her after she was abducted by Isis from her village on 3 August.
"She stated that ISIL [Islamic State] took hundreds of women who had not been able to flee to Jabal Sinjar," stated the report. "The girl stated that she was raped several times by several ISIL fighters, before she was sold to a market."
Other accounts detail how women were separated from their children and made to watch beheading videos.
Sold into slavery and gang raped
One Yazidi woman was given to 10 Islamic State men. "We were sold for $10 or $12. Who could accept that behaviour? Can God accept that?" the woman told Euronews. "It's a shame to rape a woman, but when she is raped by 10 men… what is this? They are animals, they are not humans. Because of them I am afraid all the time."
She managed to flee her captors with the help of sympathetic local residents and sought safety in Mosul.
A 17-year-old woman said she was being held captive with 40 other Yazidi women by Islamic State fighters.
"I beg you not to publish my name because I'm so ashamed of what they are doing to me. There's a part of me that just wants to die. But there is another part of me that still hopes that I will be saved and that I will be able to embrace my parents once again," she told Italy's La Repubblica newspaper.
The newspaper was able to interview her by calling her on her mobile phone, after being given the number by her parents, who are in a refugee camp in Iraqi Kurdistan.
"We've asked our jailers to shoot us dead, to kill us, but we are too valuable for them. They keep telling us that we are unbelievers because we are non-Muslims and that we are their property, like war booty. They say we are like goats bought at a market."
The UN High Commission for Human Rights reported that trade in malak yumin – war booty – is at very high levels.