Sickening footage appears to show Islamic State militants parading around 250 captured soldiers through the desert in their underwear before they are killed and their bodies piled on the bare earth.
An Islamic State fighter claimed the men were from the Syrian government's Tabqa air base which extremists seized on Sunday, handing them warplanes, helicopters, tanks, artillery and ammunition.
The video, which has not been independently verified, is too graphic to be published in full.
It begins by showing dozens of men being marched through the desert wearing only their underwear. It then fades to black, resuming with a pile of bloodied bodies stacked on top of one another.
Marched to their deaths: Sickening ISIS slaughter continues as 250 soldiers captured at Syrian airbase are stripped then led to the desert for mass execution
WARNING GRAPHIC CONTENT
Startling footage of vast pile of bodies circulated today on social media
Men in only their underwear form a long line stretching across the desert
Islamic State fighter said men were from Tabqa air base, captured this week
Human Rights Watch described shocking video as 'another ISIS war crime'
By DAN BLOOM FOR MAILONLINE
PUBLISHED: 09:18 EST, 28 August 2014 | UPDATED: 11:33 EST, 28 August 2014