The twisted terror group’s leader has issued a terrifying edict telling militants that repeatedly sexually abusing women is the best way to make them Muslim.

The sickening letter, circulated amongst the group’s warped fighters, states that a woman automatically becomes Muslim if she is raped by at least 10 different ISIS fighters.

It emerged as victims of the perverted hate group spoke out about its infamous sex slave markets, where twisted militants can buy women for as little as a packet of cigarettes.

ISIS fighters have previously executed women who refused to have sex with them, with many experts saying most young men joining the group are more interested in sex than Islam or jihad.

Many of the women come from the Yazidi religious sect and have been horrendously defiled and mutilated by Islamist fanatics who believe they indulge in “devil worship”.

One of them, known as Noor, revealed how a crazed jihadi showed her the letter from ISIS leader Abu Bakr Al Baghdadi as a form of justification before brutally raping her.

The 22-year-old was sold into slavery after ISIS overran her village in the Iraqi province of Sinjar.

She said: “He showed me a letter and said, ‘This shows any captured women will become Muslim if 10 ISIS fighters rape her.’ There was a flag of ISIS and a picture of Abu Bakr Al Baghdadi.”

Horrifyingly, she revealed how the militant then passed her on to 11 of his friends, so that they could also raped her in the name of their warped ideology.

She said: “ISIS fighters told us, ‘This is the rule of Abu Bakr al-Baghdadi and we must do it’.

“They said: ‘Anyone who doesn’t convert to Islam, we will kill the males and marry the girls. They are the spoils of war.'”