Isis fighters are committing widespread, organised and systematic rape and sexual assault on Yazidi women and girls in what may amount to a crime against humanity, a report by Human Rights Watch (HRW) has found.

HRW said fighters from Europe are among those from Iraq, Syria, other countries in the Middle East and Central Asia abusing girls and women, according to harrowing accounts from victims. The organisation spoke to girls as young as 12 after they escaped their captors in northern Iraq, who described being gang-raped by brutal fighters multiple times. Many had witnessed other women and young girls being sexually assaulted.

A doctor in charge of treating survivors in Dohuk said at least 70 of the 105 female survivors she had treated appeared to have been raped while being held hostage by the extremist group.

One woman, Rashida, described militants choosing women by drawing their names out of a "lottery". The 31-year-old says she tried to kill herself by swallowing a toxic chemical after being ordered by the fighter who picked her name to bathe.

Two girls described the abuse of their 16-year-old sister by four men over a period of several months. Their sister, who was allowed to visit them, recounted a Ukrainian fighter beating her, raping her, giving her electric shocks and denying her food.

HRW told The Independent that the 16-year-old girl is still being held hostage by Isis.

Jalila was 12 when she was separated from her family in August as they tried to flee Isis’ advance. After being stopped by a group of Arab men, she was handed over to Isis and later taken to a house in Syria, where other young girls were being held.

“The men would come and select us,” she told HRW. “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. They wore dishdashas [ankle length garments], and had long beards and hair."

Iraq crisis: Yazidi nightmare on Mount Sinjar Show all 15 1 /15 Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis Displaced people from the minority Yazidi sect, fleeing violence from forces loyal to the Isis in Sinjar town, walk towards the Syrian border, on the outskirts of Sinjar mountain, near the Syrian border town of Elierbeh of Al-Hasakah Governorate Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis Displaced people from the minority Yazidi sect, fleeing violence from forces loyal to the Isis in Sinjar town, walk towards the Syrian border, on the outskirts of Sinjar mountain, near the Syrian border town of Elierbeh of Al-Hasakah Governorate Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis Displaced Iraqis from the Yazidi community settle at a camp at Derike, Syria. In the camps here, Iraqi refugees have new heroes: Syrian Kurdish fighters who battled militants to carve an escape route to tens of thousands trapped on a mountaintop Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis A pilot based at RAF Marham entering a Tornado GR4 prior to taking off for the reconnaissance mission over Iraq. Several RAF Tornado jets set off from RAF Marham in Norfolk this afternoon to travel to a "pre-position", from where they will fly to northern Iraq to provide improved surveillance of the situation on the ground. The jets, fitted with Litening III targeting and surveillance pods, will be able to fly over the crisis area to provide intelligence and help with the delivery of humanitarian aid Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis A British Royal Air Force (RAF) Tornado GR4 aircraft equipped with the Litening III pod from RAF Marham, eastern England, on their arrival at RAF Akrotiri Cyprus for their reconnaissance mission over Iraq Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis Aid inside a Royal Air Force (RAF) Hercules C130 J aircraft before being airdropped to civilians in Iraq Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis A Royal Air Force (RAF) Hercules C130 J military transport plane at RAF Akrotiri in Cyprus. Britain made a third round of airdrops of supplies to aid refugees stranded on a mountain in northern Iraq, officials said, as Tornado fighters arrived at an RAF base in Cyprus preparing to provide surveillance support for the humanitarian effort Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis Royal Air Force (RAF) Tornado GR4 aircraft, flown in from Britain, stand on the tarmac at RAF Akrotiri in Cyprus Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis A displaced man helps a woman, both from the minority Yazidi sect fleeing violence from forces loyal to the Isis in Sinjar town, as they make their way towards the Syrian border, on the outskirts of Sinjar mountain, near the Syrian border town of Elierbeh of Al-Hasakah Governorate Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis Iraqis including Turkmen, Shabaks, Kurds, Yezidis and Christians, fleeing from assaults of army groups led by Isis, take shelter at Bahirka Camp in Arbil Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis Displaced Iraqis from the Yazidi community look for clothes to wear among items provided by a charity organization at the Nowruz camp in Derike, Syria Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis Displaced Iraqis from the Yazidi community gather for food at the Nowruz camp in Derike, Syria Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis Displaced Iraqis from the Yazidi community gather for food at the Nowruz camp in Derike, Syria Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis Syrian Kurdish Peshmerga fighters take a sick Iraqi Yazidi woman to the clinic at Nowruz camp in Derike, Syria Iraq crisis: Yazidi nightmare on Mount Sinjar Iraq crisis Sick displaced Iraqis from the Yazidi community wait for treatment at a clinic at Nowruz camp in Derike, Syria

She said an Isis fighter selected and dragged her out of the house when she tried to fight him off. “I told him not to touch me and begged him to let me go,” she 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.”

Another 12-year-old said she was abducted by Isis in August, who then took her to a school in Tal Afar which was being used to hold Yazidi captives and separated her from her family.

She said an older fighter assured her he would not harm her, and then raped her repeatedly. “He was sleeping in the same place with me and told me not be afraid because I was like his daughter,” she said. “One day I woke up and my legs were covered in blood.”

The Organisation of Women’s Freedom in Iraq (OWFI) believes that thousands of Yazidi woman have already been sold into enslavement (AFP)

Another woman, Leila, said she was brutally punished when she was discovered trying to kill herself.

“After they realised what I was doing, they beat me with a long piece of wood and with their fists," she said. "My eyes were swollen shut and my arms turned blue. They handcuffed me to the sink, and cut my clothes with a knife and washed me. They took me out of the bathroom, brought in [my friend] and raped her in the room in front of me.” Leila was raped shortly after this ordeal.

HRW’s report found many victims were struggling to access psychological help, counselling, tests for sexually transmitted infections, emergency contraception and in cases of pregnancy, safe and legal abortion.

“Isis forces have committed organized rape, sexual assault, and other horrific crimes against Yezidi women and girls,” said Liesl Gerntholtz, women’s rights director at Human Rights Watch. “Those fortunate enough to have escaped need to be treated for the unimaginable trauma they endured.”

The atrocities suffered by Yazidi sex slaves were exposed more fully in an 87-page report released by Amnesty International in November 2014, who found girls and women were repeatedly raped and sold as sex slaves.