Islamist militants in Syria have allegedly posted a remarkably disturbing video of themselves goofing off with the severed head of a man they apparently decapitated.

The Middle East Media Research Institute discovered the video, which appears to show insurgents with the Islamic State of Iraq and Syria posing with the decapitated head, joking and laughing hysterically as they swagger around with it.

This undated file image posted on a militant website on Tuesday, Jan. 14, 2014 shows fighters from the Al Qaeda linked Islamic State of Iraq and Syria (ISIS) marching in Raqqa, Syria. (AP Photo/militant website, File)

This undated file image posted on a militant website on Tuesday, Jan. 14, 2014 shows fighters from the Al Qaeda-linked Islamic State of Iraq and Syria marching in Raqqa, Syria. (AP Photo/militant website, File)

According to MEMRI, the video was posted June 15 by members of ISIS, an Al Qaeda-inspired terror group fighting to establish an Islamic caliphate in Iraq, Syria and beyond. The group noted that the head belonged to a fighter with the Free Syria Army, another rebel group trying to unseat Syrian President Bashar Assad.

TheBlaze is unable to independently verify the video, in which an ISIS militant begins by picking up the decapitated head and saying in English, “Hello, my name is John,” to which his companion shooting the cellphone video respond with hearty laughter.

“See, he doesn’t smile today. Look at him,” the unidentified ISIS member says.

Image source: MEMRI

Image source: MEMRI

The man filming the video says, “Why doesn’t John look like he died of natural causes?”

Watching the distasteful scene play out, another jihadist militant says: “Oh, disgusting … ewwww…”

The man holding the head then tosses it to the ground.

“He died of natural causes,” the man shooting the video quips.

Another ISIS member responds, “This guy died of natural causes by a knife. … It cut his throat.”

The man filming the video concludes: “Natural causes – the mujahideen. … Natural cause for an apostate. Allah Akbar.”

This latest video is reminiscent of a particularly grotesque tweet last week that was attributed to ISIS which included a photo of an Iraqi Sunni police chief’s severed head along with a disturbing joke about using it as a soccer ball.

“This is our ball…it is made of skin #WorldCup,” ISIS reportedly wrote. The Twitter account was shut down after the graphic tweet.

The video can be seen at this link, via MEMRI. CONTENT WARNING: extremely graphic images.