In a video released by the self-proclaimed 'Islamic State' (IS) militants, 25 men were shot by forces in the ancient city of Palmyra, Syria.

According to BBC, IS said these men were all soldiers, captured in Homs.

The gunmen involved in the mass execution were all very young, around 13-14 years old.

IS captured the city of Palmyra and a neighboring city, Tadmur, in late May.

In the undated video, the execution takes place at a relic of the ancient citadel area, in front of a large black IS flag.

About a hundred men in civilian clothes sat watching the murder. Among them were many minors.

The UK-based Syrian Observatory for Human Rights said several such executions took place on 27 May, but it was not clear whether these incidents were captured on video.

In another related development, a British family of 12 members joined IS.

Initial reports said the family went missing, then turned themselves in to IS and a statement on their behalf said they felt 'safer than ever'.

The family, including three children aged between 1 and 11, have been missing since May 17. Police say they may have gone to Syria.

(According to VNN)