Children in their teens are shown leading eight men to their deaths in the latest brutal beheading video released by Islamic State.

The teenage boys, known as the 'Cubs of the Caliphate', are seen holding large rifles, and walking the captives to an open field, thought to be in the central Syrian province of Hama. They order the men - Shi'ite Muslims - to kneel on the ground, before passing them over to masked militants. One of the boys, all of whom are believed to be under the age of 18, then distributes knives which are used to behead the captives.

An IS militant in the video refers to Shi'ites as "impure infidels" and pledges that his fellow fighters will continue to kill those who are trying to stop them. "Our swords will soon, God willing, reach the Nuseiries and their allies like [Syrian president] Bashar and his party," he says. Nuseiry is a derogatory term for some Shi'ite Muslims.

According to the London-based Syrian Observatory for Human Rights (SOHR), the militant also refers to the 1982 massacre in Hama that put an end to a Muslim Brotherhood uprising. Between 10,000 and 40,000 Syrian people are thought to have died in the 27 day siege.

"We will not forget what the regime did in the 80s in Hama and we won't forget any blood drop on that blessed land and as the Khalifa said, 'We will revenge'," he says.

It is the first time that children have been shown to participate in the mass execution of prisoners on behalf of Islamic State, though according to SOHR, around 400 children are believed to have joined the jihadi group since the beginning of this year.

Earlier this month, a video posted online by IS militants showed a boy fatally shooting an Israeli Arab accused of spying for Israel's intelligence service. The boy is described by an older, French-speaking fighter as one of the "cubs of the caliphate".