The Islamic State (ISIS) group on Wednesday executed 20 men in front of a crowd in the UNESCO-listed Roman theater of Syria's ancient city of Palmyra, a monitor told AFP.
Nearly a week after seizing the strategic city, ISIS gathered 20 men they accused of fighting for the regime in the ruins of the theater and shot them dead, Rami Abdel Rahman, head of the Syrian Observatory for Human Rights, told the news agency.
"ISIS gathered a lot of people there on purpose, to show their force on the ground," he said.
Syria's antiquities director said he feared the killings were a harbinger of the much-dreaded destruction of the ancient site, considered one of the world's greatest heritage jewels.
The jihadist group has damaged priceless historical sites across the region but mainly used its sledgehammers and dynamite on statues and places of worship it considers idolatrous.
It seized Palmyra on May 21, a move analysts warned positioned the group to launch more ambitious attacks on Damascus and third city Homs.
Syrian state TV on Sunday reported that about 400 civilians were massacred by ISIS since last Wednesday, while activists in Palmyra said that ISIS fighters hunted down President Bashar al-Assad's troops and loyalists, killing up to 300 of them.
With the Syrian army retreat from Palmyra, there has been talk of the Assad's regime being forced to accept the de facto division of Syria.
Reportedly 10-15% of Syria's population is now in areas controlled by ISIS – which geographically controls around half of the country's landmass, much of which is sparsely populated – while 20-25% are in territory controlled by Al-Qaeda-affiliated Nusra Front or other rebel groups, and another 5-10% are in areas controlled by Kurdish forces.