♪ ♪ >> EVAN WILLIAMS: There are tens of thousands of children now living under the control of ISIS in Iraq and Syria. Children the group is now actively recruiting as their next generation of fighters. Ten-year-old Hamude was one of them. >> (speaking world language): >> WILLIAMS: Getting independent information about ISIS military training of children isn't easy. Thousands of Syrian refugees now live in Turkish border towns. Most people are afraid to talk because they fear ISIS sympathizers are here, too. But some children were willing to speak out on condition of anonymity. This 14-year-old boy says he joined ISIS after they convinced him they were pure Muslims. >> (speaking world language): >> WILLIAMS: But when they threatened to kill his brother, he says he lost faith in ISIS and fled. ♪ ♪ ISIS propaganda videos show children being put through rigorous physical training. But boys who've undergone ISIS training say they are also being taught something much more dangerous. >> (speaking world language): >> WILLIAMS: ISIS calls these children "cubs of the caliphate." The boy says from what he saw, children are being systematically recruited across ISIS-controlled territory into the three different ISIS fighting units. >> (speaking world language): (song playing in video, men singing) >> WILLIAMS: This ISIS video shows a stage of basic training for children where they're coerced to commit violence. All of this seemingly unaffected by hundreds of coalition air strikes. It's physically hard, but the main aim is to create a new army of unquestioning, and what ISIS deems ideologically pure, fighters. >> (speaking world language): >> WILLIAMS: It's that loyalty that ISIS is exploiting for another horrifying purpose. It starts with showing the children videos of suicide attacks. >> (speaking world language): >> WILLIAMS: And how, how young would be the youngest boy that wants to be a suicide bomber, that you saw? >> (speaking world language): >> WILLIAMS: Eight? He was just a child. >> (speaking world language): >> (chanting over loudspeaker) >> WILLIAMS: Convincing young children to sacrifice their lives without question requires intensive indoctrination. We tracked down an insider who says she was in charge of that process. Until just a few weeks before we met this woman, she says she was an ISIS teacher who prepared girls as young as ten for suicide attacks. >> (speaking world language): >> WILLIAMS: She too narrowly escaped after becoming disillusioned by the violence. >> (speaking world language): >> WILLIAMS: These boys have also recently escaped ISIS-controlled Syria. Now in Turkey, they attend weekly de-radicalization classes to counter the influence of ISIS indoctrination. >> (speaking world language): >> WILLIAMS: Children are taught to spy on their parents, who risk death if they object to their children joining ISIS. Boys are routinely gathered in town squares, where they're offered money and food to join ISIS and fed anti-Western tirades. >> (speaking world language): >> WILLIAMS: This ten-year-old boy was among those ISIS tried to recruit. >> (speaking world language): ♪ ♪ >> WILLIAMS: The boys say they are sat in front of big screens and forced to watch videos of ISIS brutality, propaganda videos like this, which shows the recent execution of Syrian soldiers in Palmyra. >> (speaking world language): >> WILLIAMS: Ahmed is 11. >> (speaking world language): >> WILLIAMS: They say they are forced to watch real executions, too. >> (speaking world language): >> WILLIAMS: But perhaps most disturbingly of all, ISIS releases videos showing executions being carried out by boys themselves. >> (speaking world language) >> WILLIAMS: Like this boy, who was shown beheading a Syrian officer. Or this boy, who apparently executed two alleged Russian spies in January. >> (speaking world language) >> WILLIAMS: Boys are told they too will be killed if they don't join ISIS by age 16. But death is not the only punishment for refusing to join ISIS. Omar is 14. He had been serving with more moderate opposition forces. ISIS fighters captured and then tortured him to try to force him to join them. >> (speaking world language): >> WILLIAMS: He says he refused to join and was sentenced to a horrifying punishment. >> (speaking world language): ♪ ♪ >> WILLIAMS: These photos show Omar's actual amputation. And the man known as the Bulldozer, who he says severed his limbs. Omar's amputations were carried out just three weeks before we met him. He'd escaped Syria only days before. The price of his defiance is constant pain and depression. >> (speaking world language): (murmurs) >> WILLIAMS: Omar's public punishment was used as a warning to children not to resist ISIS. >> (speaking world language): ♪ ♪ >> (chanting in world language): >> WILLIAMS: The children of this new ISIS army are fighting in Syria and Iraq now. But they're being taught that their ultimate purpose is to also launch attacks on the West. >> (singing in world language): >> (speaking world language):