The SITE Intel Group, a watchdog group of Islamic extremists, reported on Twitter about a video ISIS released on Thursday that shows a new level of ISIS's brutality: forcing a young boy to behead a captured Syrian military officer.

The use of children in their terroristic and murderous propaganda is not new. Islamic State fighters call these youths the "cubs of the Caliphate." Many of the children, some no older than 12, have been forced to shoot the terror group's targets at close range.

This is the first video evidence of the Islamic State using a young boy to carry out a beheading.

In the video, a boy no older than 10 is seen decapitating the regime army officer, who is reportedly a commander in the city of Palmyra, reports the Daily Mail. Palmyra fell to ISIS forces in late May.

SITE Intel Group uploaded screenshots of the video to their Twitter account, condemning the use of children in executions.

The boy, dressed in camouflage and a black headdress, does not look frightened. Rather, his piercing gaze seems to show marked intent on carrying out his order. He approaches the man, pulls his head up by the hair and slices his throat. He proudly lifts the severed head before placing it on the man's back.

The execution is believed to have been conducted at the Western Hir Palace in the province of Homs after the Syrian man was caught at the Al-Bosayri army checkpoint, according to Daily Mail.

At the video's conclusion, an adult militant speaks a threat to the camera: "Our goal is not only Palmyra or Homs or Damascus, rather our goal is to conquer Bayt al-Maqdes [Jerusalem] and Rome, God willing," according to the U.K.-based Syrian Observatory for Human Rights.

The Syrian Observatory of Human Rights also reports that ISIS's "cubs of the Caliphate" have committed several crimes this year. In early January, children were coerced by the Islamic State to execute two people who had confessed to being "agents for the Russian intelligence." In late March, there was a report that nine "cubs of the Caliphate," under the age of 18, beheaded nine men.

On May 27, 25 children executed 25 soldiers of the regime forces on the Roman Theatre at Palmyra east of Homs. The video of their execution was also released online earlier this month.