A video released by Islamic State shows fighters carrying out a mass execution by beheading Syrian rebels.

ISIS threaten bloodshed against any Muslims thinking about joining US-backed groups looking to over-throw the Assad regime in the war-torn Middle East.

Two fighters talking in the video proclaim the group will not stand for anything other than an Islamic State-run Syria, before members of the Free Syrian Army - who are filmed performing Nazi salutes, say ISIS - are brutally murdered.

The final act in the 19-minute video, seen by MailOnline, sees militants dressed in black throwing members of the Free Syrian Army to the ground in the desert

The video comes from Wilayat Furat in Iraq, translated to the State of the Euphrates, according to Heavy.

Wilayat Furat an ISIS-occupied area located north of Wilayat al-Anbar on the border of Syria.

The video starts with a statement in English, saying: 'In this video production is a presentation of some recorded scenes documenting the source of the program to train the sahwat vetted by America in Jordan under the wings of the Crusader coalition forces.

'This is a small portion of what the sahwat left behind to become ghanimah in the hands of the Khilafah’s soldiers after they failed to advance on the city of Albu Kamal and their soldiers were either killed or driven out.

'And to Allah belongs all praise and favor.'

A video released by Islamic State shows Free Syrian Army fighters performing Nazi salutes before ISIS carry out a mass execution by beheading Syrian rebels

Towards the end of the video, two jihadists deliver a speech accusing the US of trying to take over the Middle East

ISIS fighters take the men, who are dressed in Guantanamo Bay-style orange jumpsuits, and behead them with small knives

It is understood this is a threat to Muslim fighters who have joined or are thinking of joining US-backed Syrian rebel groups.

Towards the end of the video, two jihadists deliver a speech accusing the US of trying to take over the Middle East.

The final act in the 19-minute video, seen by MailOnline, sees militants dressed in black throwing members of the Free Syrian Army to the ground in the desert.

ISIS fighters take the men, who are dressed in Guantanamo Bay-style orange jumpsuits, and behead them with small knives.