ISIS terrorists are using child rape to force young soldiers to join their ranks, it has been claimed.

Child soldiers are threatened with sexual assault to coerce them to join, sources have told the FNA News Agency.

But when they do join up, young soldiers are filmed being raped, and told that the footage will be released if they flee the battlefield.

It has been claimed that child soldiers are threatened with sex assaults, and then raped and told footage will be released if they flee

A source in Deir ez-Zor in Syria told the agency: 'The children who are sent to the warfronts are then again raped by adult terrorists in order to prevent them from fleeing the battlefields.'

The UN found in 2014 that more than 25,000 women and children had been taken captive in the region.