A report indicates there is evidence that members of the Islamic State (ISIS/ISIL) have forced children to play soccer with decapitated heads as a way to desensitize them to violence.

“Children not only get desensitised to violence, but they also deem these practices as normal, and eventually defend them,” wrote the researchers at the London based think tank the Quilliam Foundation. “Children have been seen accompanying prisoners to their death and, in one example, distributing knives to adults before a mass beheading.”

Their findings back numerous reports of people who witnessed children using decapitated heads. Last April, some Palestinians escaped a refugee camp after the Islamic State captured it.

“In Palestine Street, I saw two members of Daesh playing with a severed head as if it was a football,” explained Amjad Yaaqub, a 16-year-old refugee.

In June 2014, the terrorist group hijacked hashtags on Twitter associated with the World Cup, including #ENG and #Brazil2014. They posted pictures of slaughters and jihadists using heads as soccer balls.

“I saw severed heads,” described Ibrahim Abdel Fatah, 55. “They killed children in front of their parents. We were terrorized. We had heard of their cruelty from the television, but when we saw it ourselves … I can tell you, their reputation is well-deserved.”

The same report found evidence that the terrorist group has impregnated up to 31,000 women. The Islamic State has used social media to recruit women to help it populate its Caliphate since invading Syria and Iraq in the summer of 2014. Many of the women come from the UK, Australia, and the United States.

“ISIS is recruiting these women in order to be baby factories,” Mia Bloom of the Center for Terrorism and Security Studies at the University of Massachusetts Lowell said in September 2014. “They are seeing the establishment of an Islamic state and now they need to populate the state.”

The Islamic State then enrolls these children, some as young as six, into training camps. One video, titled “School of Jihad,” shows children learning how to behead and torture “infidels” and handle weapons.

“Firstly, children are a completely blank slate and so don’t have the cognitive abilities or the adult decision-making processes, so they can be manipulated because they are vulnerable to do all kinds of things,” said senior researcher Nikita Malik, adding, “The families play a key role in doing this as well. Mothers play a key role: they read story books on martyrdom to their children at night. The families are teaching them what is right and wrong. This purity angle is very interesting.”

The group also released a video in August 2014 with Omar al-Shishani, a prominent Chechen leader in the Islamic State. One of the oldest kids shows his ability to quickly take apart the gun, reattach it, and load the ammunition. After that, the children hide behind a wall and perform a mock military exercise for al-Shishani.