Survivors of the Islamic State (ISIS) reign of terror in the Middle East have been telling horrific tales that can chill people's bones down to the spine.

A Christian mother and her son who managed to escape the clutches of ISIS told the Catholic charity Aid to the Church in Need that they witnessed forced conversions to Islam as well as the training of child killers.

Jandark Benham Mansour Nassi, 55, and her son Ismail, 16, were seized by ISIS fighters from their home in Bartella, a predominantly Christian town in Northern Iraq, and taken to Mosul.

"I was very afraid," said Jandark, a widow. "Our names were written down, and we had no idea where we were and what would happen to us. We were completely shut off from the outside world. Shortly after, we received permission to return to Bartella, but at a checkpoint we had to convert to Islam and when we refused, they hit us. My son was put in prison. He was only 14 years old."

In prison, Ismail saw gun-toting jihadi children, the so-called "cubs of the caliphate," who he said were being taught to kill ISIS captives. "Once, when I was going to the mosque with the jihadists early in the morning, our path was blocked," he recalled. "Suddenly we were passed by men in orange suits, held at gunpoint by a group of Daesh children. The children executed them with pleasure."

Another time, Ismail ran into a big crowd on the street and saw a woman with her hands and feet tied. The terrorists drew a circle around her and told her she would live if she managed to get outside the circle. However, Ismail said it was impossible given how she was tied.

"While her relatives were crying and begging for pardon, the jihadists threw stones at her until she died," he said.

Personally, Ismail said the jihadists threatened to kill him if he did not to convert to Islam. Out of fear, he agreed. He was even forced to go to a "correctional camp" and learn the Quran. They also wanted him to marry one of their own, but Ismail objected, saying he was still too young.

As for his mother, they tortured her for not knowing anything about their religion. "Men were obligated to pray in the mosque on Friday. Anyone who would walk on the streets during the Friday prayer would be beaten. In the mosque, we were told that Assyrians were evil and that Christians did not believe in the right way," he said. "My mother should have to pray at home but she did not pray to Allah."

Thankfully, Ismail and his mother was able to find safety in Erbil, where thousands of Christians are now seeking refuge. "Daesh snipers tried to shoot us. We ran for cover into a house. After hours of fighting, my mother and I were able to leave the house, waving a white flag. Soldiers of the Iraqi liberation army welcomed us. We were free," Ismail said.