Hundreds of teenage girls held captive by militants of the Islamic State group are being sold in slave markets for “as little as a pack of cigarettes,” Zainab Bangura, the United Nations special representative on sexual violence in conflict, alleged. Her comments, made on Monday, form the latest in a series of similar accusations leveled against the Sunni militant group that currently controls large swaths of Syria and Iraq.

“They [ISIS militants] kidnap and abduct women when they take areas so they have -- I don’t want to call it a fresh supply -- but they have new girls,” Bangura, who visited Iraq and Syria in April, told Agence France-Presse (AFP). “This is a war that is being fought on the bodies of women.”

Bangura’s comments were based on her interactions with several teenage girls who had managed to escape from ISIS' captivity.

“Some were taken, locked up in a room -- over 100 of them in a small house -- stripped naked and washed. ... They were then made to stand in front of a group of men who decided ‘what you are worth,’” Bangura told AFP.

The allure of sex slaves is being used by ISIS to attract foreign fighters, Bangura alleged. According to recent estimates, there are up to 25,000 foreign jihadists fighting for ISIS in Syria and Iraq.

“This is how they attract young men -- we have women waiting for you, virgins that you can marry,” she told AFP.  

While it is hard to estimate the exact number of women and girls enslaved by the group, slave markets are believed to be commonplace in areas under ISIS’ control.

In a report released in December -- just months after a video showing ISIS members discussing the sale of girls at a slave market emerged -- Amnesty International alleged that thousands of women and girls, many of them as young as 12, belonging to Iraq’s Yazidi community, were raped, tortured and beaten by militants of ISIS who sold them to sexual slavery. This had reportedly driven many women of the persecuted minority community to suicide.

“The IS has not tried to hide or deny its crimes. On the contrary, more than any other group, it has gone to great efforts to publicize gruesome details of the atrocities perpetrated by its members against captured soldiers and civilians alike, giving them ample resonance through videos and statements widely distributed on social media, often in multiple languages,” Amnesty said in the report.

Earlier in May, Bangura had accused ISIS of making sexual violence and brutalization of women and girls a “central aspect of its ideology and operations.”

“We also need to look not only at ending impunity but also deterrence, and this is much more challenging when you are dealing with actors who have no respect for international human rights law or international humanitarian law,” she reportedly said.