Girls as young as nine are reportedly being forced into "pleasure marriages" and made to have sex with dozens of men.
In Iraq, unmarried couples aren't permitted to have sex, so the Islamic marriage arrangement means men can wed young girls for a few days or even hours - just so that they can have sex with them.
After being paid a few hundred dollars as a dowry, the women are forced into a quick wedding ceremony, after which they are expected to have sex with their new husband - who is usually much older than them.
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According to The Sun, the sex acts are often violent and forceful, and younger, "fresh" girls are the most expensive to "buy".
"I'm forced to do things I don't want. Even if I resist, it still happens," one of the bride's told The Sun, who has lost count of the amount of times she's been married off.
Despite the legal age of marriage in Iraq being set at 18, one cleric told The Sun he would be happy to officiate a marriage between a 12-year-old girl and an undercover reporter.
"Nine years plus, there's no problem at all. According to sharia, there's no problem," he said.
"You can marry a girl for half an hour and as soon as it's over you can marry another one straight away," agreed another.
A new BBC documentary, "Iraq's Secret Sex Trade", is set to delve into the illegal practice, and includes interviews with women who have repeatedly been sold off for sex, trapped in prostitution rings and driven to contemplating suicide.