Image copyright Reuters

The Islamic State group has released footage showing five boys, including one it identifies as British, carrying out the killing of prisoners in Syria.

The children appear to be about 10 to 13 years old and the boy captioned as Abu Abdullah al-Britani is white.

The video shows the children shooting dead five men identified as captured Kurdish fighters who are kneeling.

The identity of the boy said to be British could not be verified and the Foreign Office has not commented.

The child is pictured in full military fatigues and a black hat alongside four other boys, and the prisoners are wearing orange jump suits.

One of the children, identified as Abu al-Bara al-Tunisi (the Tunisian), addresses the Kurdish fighters in Arabic, promising more violence and saying the battle against them has not yet begun.

The other children are captioned as Abu Ishaq al-Masri (the Egyptian), Abu Abdullah al-Britani (the Briton), Abu Fu'ad al-Kurdi (the Kurd) and Yusuf al-Uzbaki (the Uzbek).

Children have featured prominently in Islamic State propaganda in which the militant group boasts about preparing the next generation of fighters.