The Islamic State group consolidated its control of the Iraq-Syria border on Friday after capturing an Iraqi provincial capital and a famed Syrian heritage site in an offensive that has forced a review of US strategy.
The militants, who now control roughly half of Syria, reinforced their self-declared transfrontier “caliphate” with the capture of the al Tanaf to al Walid crossing on the Damascus-Baghdad highway late on Thursday.
It was the last border crossing with Iraq still held by the Damascus government. Except for a short section of frontier in the north under Kurdish control, all the rest are now held by IS.
The militant surge, which has also seen them capture Anbar capital Ramadi and the ancient Syrian city of Palmyra in the past week, comes despite eight months of US-led air strikes aimed at pushing them back.
It has sparked an exodus of tens of thousands of fearful civilians in both countries and raised fears that the militants will repeat at Palmyra the destruction they have already wreaked at ancient sites in Iraq.
President Barack Obama played down the IS advance as a tactical “setback” and denied the US-led coalition was “losing” to IS.
But French President Francois Hollande said the world must act to stop the extremists and save Palmyra.
UNESCO chief Irina Bokova called the 1st and 2nd Century ruins “the birthplace of human civilisation”, adding: “It belongs to the whole of humanity and I think everyone today should be worried about what is happening.”
As the militants fanned out across Palmyra on Thursday, they went door to door executing suspected loyalists of the Damascus government, the Syrian Observatory for Human Rights said.
At least 17 people were killed, the Britain-based monitoring group said.
Syrian state media said loyalist troops withdrew after “a large number of IS terrorists entered the city,” which lies at a strategic crossroads between Damascus and the Iraqi border to the east.
IS proclaimed Palmyra’s capture online and posted video and stills footage of its fighters in the city’s air base and prison, long notorious for its detention of regime opponents.
The militants did not immediately post pictures of the UNESCO-listed world heritage site with its colonnaded streets, elaborately decorated tombs and temples.
IS sparked international outrage this year when it blew up the ancient Assyrian city of Nimrud in northern Iraq.
