Eight months after Islamic State extremists kidnapped hundreds — possibly thousands — of Yazidi women and girls from their centuries-old homeland in northern Iraq, the rape and extraordinary suffering they have experienced at the hands of their captors is falling into starker relief.

The latest accounts of the abductees' fates come from Human Rights Watch (HRW), which recently interviewed 11 women and nine girls who were able to escape detention and flee to Kurdish controlled areas between September 2014 and January 2015. In a report released on Wednesday, the rights group said many of the Yazidis, including two 12-year-olds, had been sold among fighters and raped, and most were forced to marry their captors.

"The men would come and select us," said Jalila, a 12-year-old girl who was kidnapped by the Islamic State (IS) — also known as ISIS, ISIL, or Daash _—_from a village near Sinjar, Iraq. "When they came they would tell us to stand up and then examine our bodies. They would tell us to show our hair and sometimes they beat the girls if they refused."

In March, the UN High Commissioner for Human Rights released a delineation of IS crimes and concluded it was likely the group had committed genocide against the minority Yazidis.

Upon seizing wide swaths of northern and eastern Iraq in summer 2014, IS summarily executed hundreds of Yazidi men and abducted an unknown number of females, who they admitted to treating as "spoils of war." In September, UN human rights officials in Iraq told VICE News that the number of women and girls held by IS could be as high as 2,500. Reports from that time that indicated some of the women were being sold and raped have since been confirmed by the UN and human rights groups.

In an October 2014 publication, IS argued that Yazidis could be treated as "slaves" because they are non-Muslim. That purported interpretation of Islamic doctrine and law was universally refuted by Muslim scholars that VICE News has spoken with in the months since. Despite condemnation from countless figures of great religious authority in the Sunni Muslim world — a community IS claims to represent with their self-styled caliphate in Syria and Iraq — the group continues to hold roughly 3,000 Yazidis hostage, according to UN estimates.

In Wednesday's HRW report, Jalila, who like all the interviewees was not identified by her real name, said one of the bearded IS fighters took her against her will, slapping her and dragging her away when she refused to accompany him. "I told him not to touch me and begged him to let me go," Jalila said. "I told him to take me to my mother. I was a young girl, and I asked him, 'What do you want from me?'" He spent three days having sex with me."

Before escaping, Jalila was "owned" by seven different militants, four of whom raped her repeatedly. "Sometimes I was sold. Sometimes I was given as a gift," she added. "The last man was the most abusive; he used to tie my hands and legs."

Other girls and young women told HRW similar stories. Dilara, a 20-year-old Yazidi, said fighters would begin arriving early in the morning to "buy girls and rape them." She continued: "They were like animals… Once they took the girls out, they would rape them and bring them back to exchange for new girls."

This week, in its annual report on sexual violence in conflict, the UN drew specific attention to the crimes of extremist groups like IS and Nigeria's Boko Haram. Monday's report, nominally authored by Secretary-General Ban Ki-moon, warned that transnational terror organizations are using sexual assault and rape as an explicit "tactic of terror."

The pattern of sexual violence is "integrally linked with the strategic objectives, ideology and funding of extremists groups," said Ban.

'They are using social media to implement a medieval mentality, that women have no rights, that we can sexually abuse them, and even sell them.'

In his recommendations, the secretary general urged the UN Security Council to consider sexual violence as an act of terror and called on the Security Council Sanctions Committees that track designated terrorists to "fully integrate the issue of conflict-related sexual violence."

Zainab Bangura, who worked on the report in her role as UN special representative on sexual violence in conflict, told VICE News that those recommendations were vital, as extremist groups are transnational actors, and pose problems to existing frameworks for tracking and punishing those who carry out sexual violence.

"It will send a signal that addressing sexual violence is included in our work on counterterrorism," said Bangura. "It can get security sector institutions like militaries and intelligence to focus on the issue."

Bangura said the ability for UN human rights workers to track sexual violence is limited in Syria and Iraq, and in Nigeria, where Boko Haram is estimated to have kidnapped some 2,000 people, among them 276 schoolgirls from Chibok in the north of the country.

Paradoxically, the inaccessibility of areas under IS control is pierced by social media accounts from fighters and those loyal to the group, which reference their treatment of women. "They are using social media to implement a medieval mentality, that women have no rights, that we can sexually abuse them, and even sell them," said Bangura.

Liesl Gerntholz, executive director of HRW's women's rights division, told VICE News that punishing members of IS and Boko Haram will be difficult, but reporting their crimes is essential, if only for helping the roughly 500 women and girls she said have escaped from the clutches of the two groups.

"We hope that at some point perpetrators will be held accountable, that in the not so distant future there will be some process where this evidence will be presented," said Gerntholz. Those that have escaped, like the girls interviewed by HRW, need access to medical care, psychological services, and possibly abortions — which are illegal in Iraq — if they have been impregnated by their rapists, she said.

Like Bangura, Gerntholz said the Security Council needs to step up to help victims of sexual violence. "They have a fairly serious arsenal of tools they can use to monitor, track and respond to sexual violence, but they don't always use them as well as they could," she noted.