An RAF drone strike has prevented the public execution of two Islamic State (Isis) prisoners in Syria it was announced by the Ministry of Defence.

The remote-controlled Reaper drone, which was being operated by pilots in the UK via satellite, identified a group of fighters gathered in the town of Abu Kamal in eastern Syria as members of Daesh during a routine reconnaissance mission, and opened fire.

"When a van then unloaded two shackled prisoners in front of the crowd, it became clear that Daesh were organising a public execution," read a statement from the MoD.

The 10 metre-long MQ-9 drone, which is equipped with cameras and armed with laser guided bombs and four Hellfire missiles, spotted Isis fighters acting a sentries on a nearby rooftop and unleashed a missile directly, killing one of them.

It is understood the strike resulted in the crowd to panic and force the militant fighters to flee, putting the execution to an immediate halt.

"Given the large number of civilians present, the Reaper's crew could not target directly the Daesh fighters about to carry out the murders.

"However, two armed extremists were stationed as sentries on the roof of a building overlooking the scene. A Hellfire missile was fired immediately, and scored a direct hit which not only killed one of the sentries but also brought the execution to an immediate halt, as the Daesh fighters fled the scene, and the crowd of civilians dispersed," said the MoD.

Reaper Drone RAF Isis
How the MQ-9 Reaper works.Reuters

While the public execution on 9 May was prevented on this occasion the fate of the prisoners remains unknown, with no further information provided on whether they managed to escape during the strike or were taken away. No video footage of the incident has been released.