Filmed in the ISIS stronghold of Mosul, the sickening seven minute long video uses expensive underwater cameras to film the terrified men as they sink below the surface with no hope of escape.

Shortly afterwards the cage is lifted back out of the water, with the dying men - who are understood to have been accused of spying - seen foaming at the mouth as they lie motionless on the floor of the cage, piled on top of one another.

Elsewhere in the video, ISIS militants are filmed brutally killing prisoners by locking them in a car and shooting them with a grenade launcher, while another group of jihadis chain a set of prisoners together with explosive necklaces which are then detonated.

The barbaric video is a new low for the terror group, whose catalogue of horrific filmed murders includes the savage beheading of several British and American hostages, the burning to death of Jordanian pilot Moaz al-Kasasbeh and numerous clips of people being shot and stoned to death.

The main section of the film begins with the stomach-churning sight of five men being locked in a tiny metal cage that has been suspended above a luxury swimming pool somewhere in the ISIS-held city of Mosul in Nineveh province. 

Standing up straight with their legs bound, the men look reasonably calm until the moment the cage begins to be lowered into the pool.

As the water begins to enter, the victims start to panic, praying and pacing the tiny metal cell.

Once completely submerged, the video cuts to the high-tech underwater cameras, which show the men thrashing around until they appear to lose conciousness and fall to the floor. 

The cage is then removed from the pool, with the dying men seen foaming at the mouths as they lie piled on top of one another under the blazing Iraqi sun.

The footage is actually divided into three separate sections, with different horrific punishments reserved for each group of doomed prisoners. 

The full seven minute video actually begins by showing a group of men wearing orange jumpsuits being led into a desert clearing, before being locked in an Opel saloon car.

Moments later a masked ISIS jihadi appears carrying a huge grenade launcher, which he uses to fire a missile into the vehicle, causing it to burst into flames and burn the badly injured victims to death.

The film then cuts to interviews with another set of prisoners, where they 'confess' to the crimes they have been accused of and discuss how they have been treated by the Islamic State.

Next comes the harrowing drowning segment, which is followed by more interviews with prisoners.

The seven men are subsequently seen being led out into a field, where explosive cables are tied around their necks. 

Seconds later the explosives are detonated, with HD cameras capturing the murder in full detail.

Several of the men are clearly decapitated by the massive blast, while others suffer horrific and fatal upper body injuries. 

The latest sickening murder video was released by ISIS' Ninevah branch, which is based in the terror group's stronghold, Mosul.

Yesterday it emerged that a US airstrike near the city killed an ISIS operative who was a person of interest in the 2012 Benghazi attack.

Pentagon spokesman Colonel Steve Warren said Ali Awni al-Harzi of Tunisia was killed on June 15.

The US Treasury and the State Department had designated him as a terrorist operating for radical groups.

'His death degrades ISIL's ability to integrate North African jihadists into the Syrian and Iraqi fight and removes a jihadist with long ties to international terrorism,' Warren said referring to ISIS.

Harzi was considered a person of interest in the militant attack on the US mission in the eastern Libyan city of Benghazi on September 11, 2012, that killed the American ambassador and three other Americans.

In its terrorist designation in April, the US State Department described Harzi as a 'high-profile' member of a radical group in Tunisia who helped recruit volunteers to fight in Syria.

(dailymail.co.uk)