More than 150 Syrian soldiers were stripped and marched into the desert to be shot by Islamic State militants, activists have claimed.
A video has been posted to YouTube purporting to show the men, who are barefoot and in their underwear, being escorted into the desert.
It then goes black before revealing a similar number of men, also in their underwear, lying dead in the sand.
The video has yet to be verified but correspond to other reports from the region, and tie up with a statement and claims made via Twitter relating to the mass killing of troops captured in recent fighting for a string of military bases in north-eastern Syria.
There has been no immediate comment from the Syrian government.
More top news
After the thundery activity overnight, clears skies follow leading to a sunny, humid day. Then more thundery outbreaks to come.
A British Army nurse is to be awarded the OBE for her role in the "vanguard" of efforts to control the deadly Ebola disease in Sierra Leone.
Leaders in France and Britain today pledged to work together and increase funds to help stop migrants smuggling their way across the Channel