Article content continued

The Observatory said around 120 captive government troops from Tabqa were killed near the base. Islamic State fighters killed at least another 40 soldiers, most of whom were taken prisoner in recent fighting for other bases in the area, in the Hamrat region near Raqqa city, the group’s stronghold.

A statement posted online and circulated on Twitter by supporters of the Islamic State group claimed the extremists killed “about 200” government prisoners captured near Tabqa.

It also showed photographs of what it said were the prisoners: young men stripped down to their underwear marching in the desert. The photos could not immediately be verified, but correspond to other AP reporting.

A video that emerged online purportedly showed Islamic State fighters escorting nearly 200 men, stripped down to their underwear and barefoot, through the desert. Another video posted online later showed more than 150 men, also in their underwear, lying motionless — apparently dead — in a row in the sand.

“Yes, we have executed them all,” an ISIS fighter told Reuters in an interview conducted over the Internet.

Warning: Graphic content

While the videos could not be independently confirmed by the Associated Press, they appeared to illustrate the claims made online by Islamic State group supporters and Syrian activists about the mass killing.

There was no immediate comment from the Syrian government.

In its rise to prominence over the past year, the Islamic State group has frequently published graphic photos and videos online of everything from beheadings of opponents to mass killings.