ISIS has been putting up posters throughout Mosul, one of the captured Iraqi cities, telling residents to bring their unmarried daughters to ISIS soldiers, according to a report from the Clarion Project, a respected nonprofit organization that works to expose Islamic extremism, primarily through documentary films it produces.

Citing Arabic sources including those inside Mosul, the report said the posters call for girls to participate in "jihad al-nikah," or "sex jihad."