The Islamic State (IS) terror organisation uses the sexual slavery of women and girls to control territories and recruit radicals into its ranks, says a report.

New York Times reported that IS justify the brutal acts, because the Koran “condones and encourages” raping of women.

In a story full of shocking moments, the testimony of a 12-year-old girl, gagged, bound and raped by an IS fighter is harrowing.

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“He told me that according to Islam he is allowed to rape an unbeliever,” she told New York Times.

“He said that by raping me, he is drawing closer to God.”

According to the story, the “systematic” rape of women and girls from the Yazidi religious group has become deeply entrenched in IS theology since it said it was reviving slavery.

As a result of interviews with 21 women and girls who recently escaped IS and examination of its official communication, New York Times reports it has been “illuminated” on the group’s rape conduct.

A network of warehouses exist where Yazidi women and girls are kept and marketed to buyers. There is also a dedicated fleet of buses to move them.

A reported total of 5,270 Yazidis were abducted in 2014, with just over 3,000 still being held.

“Every time that he came to rape me, he would pray,” said a 15-year-old girl who was captured by IS.

“He kept telling me this is ibadah,” she said, the term a word from Islamic scripture meaning worship.