A woman was forced to 'restore her virginity' 20 times after abuse before marriage to Isis fighters

UN official says Isis are spreading sexual violence in "a widespread and systematic manner"

An Isis terrorist group forced a sex slave to undergo surgery to "restore her virginity" every time she was married to 20 fighters, a United Nations official has said.

Zainab Bangura, special envoy on sexual violence in conflict, has interviewed dozens of sexual abuse victims in the region.

She said sexual violence is being committed strategically, in a widespread and systematic manner, and with a high-degree of sophistication by most parties to the conflict in Syria and Iraq.

The group of Isis (also known as Isil or Islamic State) fighters would strip the victims naked and categorise them before trading them in “slave bazaars” and shipping them to other provinces.

She said: “Isil have institutionalized sexual violence and the brutalization of women as a central aspect of their ideology and operations, using it as a tactic of terrorism to advance their key strategic objectives.

The UN report also stated that in February militants fighting in Syria were seeking medical attention to improve their sexual prowess, subjecting their wives to 'brutal, abnormal' sex acts, according to local doctors.

Girls as young as five years old were kidnapped from homes and were raped and abused, according to survivors. Some were returned home when pregnancy occurred, and faced ostracism from their communities.

Women have also been pressured to "restore their virginity" after rape, in a procedure under local anaesthetic to "repair" the hymen using dissolvable stitches.

It aims to reconstruct the membrane so it can be broken again on the woman’s wedding night in cultures where blood is required as proof of virginity.

Human Rights Watch has urged the Kurdish and Iraqi authorities to provide rape victims with long-term psychosocial care.