***THE CONTENTS OF THIS VIDEO CANNOT BE INDEPENDENTLY VERIFIED BY REUTERS. CONTAINS GRAPHIC CONTENT***<br/> <br />These men are reportedly Syrian army soldiers taken prisoner by Islamic State fighters after the rebel group stormed their base in the northeastern part of the country.<br/> <br />In this latest video, first posted to a social website, fighters can be heard jeering at their hostages, refering to them as sheep and ordering them to keep moving.<br/> <br />IS fighters seized the Tabqa air base on Wednesday, posing on top of aircraft , brandishing weapons....and taking prisoners.<br/> <br />Later, they are heard interrogating one of their captives..<br/> <br />(natsot)<br/> <br />The exchange ends with the fighters saying --- We will return you to Hell, God willing. We will cut your throat."<br/> <br />..and then, apparently, the killing began.<br/> <br />The final video shows lines of dead bodies, at least 135 of them. The group claims they killed a total of 250 soldiers after capturing the base which was the g
