(CNN) Thousands of North Korean women and girls are being trafficked and sold into sexual slavery in China, where many are sold as wives to Chinese men while others are forced into prostitution or to live stream sex acts against their will, a new report claims.

The investigation, by the London-based Korea Future Initiative (KFI), includes shocking first-hand reports of girls as young as 12 being raped and women being forced to participate in cybersex for days without eating.

Though female defectors have long been targets of human traffickers, the problem has been exacerbated in recent years due to what the reports claims is a spike in demand inside of China.

China's Ministry of Foreign Affairs did not immediately respond to a request for comment.

There are no official statistics on the number of North Koreans that leave the country and settle outside South Korea. Aid groups have reported that tens of thousands of North Koreans live in China as refugees, according to a 2014 United Nations report. The KFI claims the number could be as high as 200,000.

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