Tens of thousands of North Korean women and girls — some as young as 9 — are being trafficked into sexual slavery in China as they try to flee poverty and oppression in their homeland, experts on the reclusive state said Monday.

The sexual exploitation of North Koreans generates at least $105 million in annual profits for the Chinese underworld, according to a report by the nonprofit Korea Future Initiative, which includes harrowing accounts from trafficked women.

"Victims are prostituted for as little as 30 Chinese yuan ($4.30), sold as wives for just 1,000 yuan, and trafficked into cybersex dens for exploitation by a global online audience," the report's author, Yoon Hee-soon, said.