A nine-year-old girl living within Isis-held territories was openly raped in a hall where she was being detained alongside other women, it has been claimed.

The distressing report appears in the wide-ranging analysis Children of the Islamic State, released by the London counter-extremism think-tank Quilliam, which has investigated how the terror group indoctrinates children.

Girls, it claims, are known as the “pearls of the caliphate” and must remain veiled, hidden, confined to the home, and taught to look after husbands. In one particularly disturbing case study used by the authors of the report, two young women allege that they had been raped by Isis members or fighters associated with the extremist group.

One of the women described how she heard “screams of girls who had been taken to from the main hall” where she and others were detained. Another Isis fighter pointed a gun at young girl who had been resisting.

The women were then escorted from Mosul to a school in Tal Afar, a district in northwestern Iraq, where there were “more than 100 small children”. The report adds: “The second girl said she was raped in a hall where she was being detained with other women in Mosul after her abduction by IS. She said the guards raped her three times a day for three days.

“According to her account, she also saw an eight or nine-year old girl being raped openly in the hall. IS then moved her and other women and girls to an abandoned school in Tal Afar.”

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In a separate account a young woman recounted that, after her capture in Sinjar in August 2014, she moved to Tal Afar with a hundred other girls and young women.

“After several days, she and a thirteen-year-old girl were sold to IS fighters. The fighter who bought her raped her and if she tried to resist, he would beat her with his shoes. She reported, ‘I used to hear a lot of cries and screaming from the other girl in the house, as God knows what the man was doing to her. She was too young to understand and probably was very scared.”

In the same report, it was claimed that more than 31,000 pregnant women living within Isis-held territories were being used to create the next generation of terrorists. Nikita Malik, a senior researcher at Quilliam, told The Independent: “There’s a systematic creation of the next generation of mujahideen – the next generation of fighters.”

Inside Isis secret tunnels Show all 7 1 /7 Inside Isis secret tunnels Inside Isis secret tunnels Network of underground tunnels was discovered by Kurdish forces after they regained the town of Sinjar in Iraq Inside Isis secret tunnels A member of the Peshmerga forces inspects a tunnel used by Isis militants in the town of Sinjar, Iraq Reuters Inside Isis secret tunnels An entrance to the tunnel used by Islamic State militants is seen in the town of Sinjar, Iraq Inside Isis secret tunnels The secret tunnels allowed militants to freely move underground Inside Isis secret tunnels The tunnels appear to be wired with electricity Inside Isis secret tunnels Some of the tunnels are 30 feet deep Inside Isis secret tunnels Concerns remain that parts of the tunnels are rigged with explosives

She added that it “shows it’s not being done randomly in any way, this is a very long-term preparation for these children to grow up with severe religious, theological and national indoctrination.”

Details of the so-called Islamic State’s treatment of women has been well documented by the United Nations Assistance Mission in the region. In January, it claimed those being held as slaves by Isis are “predominately women and children and come primarily from the Yezidi community”.