Islamic State militants have ratcheted up their savagery with a horrific video showing an executioner hacking off a prisoner's hand and foot while he is tied to a cross.

In shocking footage which has plumbed to new depths of depravity - even by ISIS's sickening standards - the knife-wielding jihadist is seen slicing off the man's limbs as he hangs helplessly from the wooden stake.

After the barbaric attack, the video then zooms in to show the man's corpse - dressed in an orange Guantanamo-style jumpsuit - hanging lifelessly in the middle of the desert.

Chillingly, the four-minute video even includes a 'confession' with the man before he is executed. The terror group claims it carried out the brutal killing because the man, believed to be from Iraq, was working as a spy.

Islamic State militants have ratcheted up their savagery with a horrific video showing an executioner hacking off a prisoner's hand and foot while he is tied to a cross

The disturbing film, which is too graphic to publish, is entitled 'Deterring the Spies 1', suggesting it is the first instalment in a series of similar executions which are due to take place.

Aymenn Jawad Al-Tamimi, a research fellow at the Middle East forum, said the jihadist speaking on the video mentions four other 'spies' who are still due to be tried and executed by the militants. One of them allegedly facilitated contact with the Peshmerga, the militant claims.

The slicky-edited video has all the hallmarks of an official ISIS release, employing HD cameras, Hollywood-style sound and visual effects.

The footage begins with a masked militant speaking to the camera, against a back drop of Arabic music, which was also used in the video of the execution of the 'Israeli spy'.

It includes the chilling lyric: 'We destroy what is despicable and haughty, in monstrosity his world has become agitated.'

According to Mr Jawad Al-Tamimi, who watched the video for MailOnline, the jihadist claims on camera that the man visited a secret place in the desert on a daily basis, to meet with officers in Kurdish army intelligence.

After being arrested by ISIS security forces, he was interrogated. The footage then cuts to a scene which shows the prisoner, who is visibly distressed, being questioned by his capturer and 'confessing' to his crimes.

A quote from the Qur'an is then shown. It reads: 'The penalty for those who wage war against Allah and His Messenger... is none but that they be killed or crucified or that their hands and feet be cut off from opposite sides or that they be exiled from the land.'

The slickly-edited video - which is too shocking to publish - begins with a masked militant speaking to the camera about the terror group's next victim

The footage moves to the desert, where the man bows his head in preparation for his killing.

In the most haunting scene, the killer - who is not wearing a mask - then swings his hunting knife towards the man's right hand, before attacking the man's left foot, as he cries out in pain.

The video comes just hours after ISIS released images showing a prisoner being decapitated, in a sickening echo of the executions carried out by British militant Jihadi John.

The footage shows the victim being forced face down in the dirt before having his head yanked back as the fanatic takes the knife to his throat.

The distressing images appeared to be a desperate attempt to deflect attention away from yesterday's embarrassing defeat in Tal Abyad that has now cut off their key supply route in Syria.