An RAF Reaper drone interrupted a public execution by the Islamic State group after opening fire on the militants and driving them off, the Ministry of Defence has said.

The remote-controlled aircraft disrupted the display in a Syrian town by killing a sentry with a Hellfire missile.

Details of the incident on May 9 were revealed on Tuesday by the MoD.

The Reaper was flying an armed reconnaissance mission when it spotted a group of fighters from Islamic State in Iraq and Levant (Isil), also known as Daesh, in a main street in the town of Abu Kamal.