Islamic State jihadists boasted today they had executed scores of Syrian troops after capturing a key air base, the latest in a string of abuses that have shocked the world.
News of the killings came as US President Barack Obama weighed air strikes on IS positions in Syria and edged closer to greenlighting a mission to aid Shiite Turkmen trapped in an Iraqi town besieged by the jihadists.
It also came as rival Islamist rebels led by Al-Qaeda affiliate Al-Nusra Front seized 43 UN peacekeepers on the Golan Heights, part of a mission that has monitored an armistice between Syrian and Israeli troops on the strategic plateau for decades.
IS posted grisly video footage on the Internet of scores of bodies heaped in the desert they boasted were those of Syrian soldiers they captured and executed following its seizure of Tabqa air base.
The jihadists have repeatedly posted gruesome videos, which have appalled international opinion but served as a propaganda tool to recruit volunteers.
Britain-based monitoring group the Syrian Observatory for Human Rights said that IS had executed at least 160 soldiers, among some 500 who had made a desperate bid to escape to government-held territory after their defeat last Sunday.
The footage posted by IS showed a close-up of some 20 bodies, but then panned out to show scores more.
Other shots showed men barefoot and dressed only in their underwear walking in line with their hands on their head in surrender, escorted by jihadist gunmen.
One held up the black flag of the jihadists. Others chanted, 'Islamic State forever'.
Tabqa was the last position in Raqa province to fall to the jihadists, who now control a vast swathe of northeastern Syria and Iraq.
A UN-mandated probe has charged that public executions, amputations, lashings and mock crucifixions have become a regular fixture in jihadist-controlled areas of Syria.
Obama was to meet with top national security aides at 2000 GMT to decide whether to expand US air strikes launched against IS in Iraq earlier this month to its strongholds in Syria.
The Syrian government launched air strikes of its own today, killing six IS leaders, the Observatory said, but Washington has so far baulked at cooperating with Damascus against the group.
