An Islamic State fighter, waving a flag, cheers as he takes part in a military parade along the streets of Syria's northern Raqqa province, June 30, 2014. REUTERS

A new video released by the Islamic State group, also known as ISIS, showed three children executing men in Syria’s northeastern Deir ez-Zor city. The three men were killed, allegedly in a playground, over allegations of spying for the Kurdish forces.

A 4-year-old child is among the executioners, who were dubbed the "Cubs of the Caliphate," according to reports. He is seen holding a gun, aiming at a man whose hands are tied on a net in an abandoned ball pit. The child fighter then shoots the man in the head.

Another child — reportedly a 9-year-old — executed a man by slitting his throat with a large knife after being ordered by an ISIS militant. The young fighter is seen angrily looking at the victim prior to the execution.

A third executioner is identified as 13-year-old Khattab al-Kamishli who beheads another man, according to ARA News, a Syrian news agency. In the video, the boy reportedly said that his brother was killed by Kurdish troops and by “beheading this spy” he avenged his brother’s death.

“ISIS has been kidnapping children and forcing them to join jihadist training camps in Raqqa [Syria], Deir ez-Zor and Mosul [Iraq]. They’ve been forced into committing such atrocities on behalf of the ISIS self-proclaimed Caliphate,” Omar Abu Laila, director of Deir ez-Zor 24 news network, told ARA News.

In August 2016, ISIS released a video showing five children executing prisoners in Raqqa province. One of the executioners was reportedly a British boy said to be Abu Abdullah al-Britani. The nationalities of the other alleged child executioners were reported to be Egyptian, Kurdish, Tunisian and Uzbek. The 9-minute video shows all children in military uniforms and black head covers targeting the five kneeling hostages identified as “atheist Kurds” and “spies.”