Damascus---The Islamic State group consolidated its control of the Iraq-Syria border 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 jihadists, who now control roughly half of Syria, reinforced their self-declared transfrontier "caliphate" by seizing Syria's Al-Tanaf crossing on the Damascus-Baghdad highway late Thursday.
It was the last regime-held border crossing with Iraq. Except for a short section of frontier in the north under Kurdish control, all the rest are now held by IS.
The jihadist surge, which has also seen it take Anbar capital Ramadi and the ancient Syrian city of Palmyra in the past week, comes despite eight months of US-led air strikes.
It has sparked an exodus of tens of thousands of civilians in both countries and raised fears IS will repeat at Palmyra the destruction it has already wreaked at ancient sites in Iraq's Nimrud and Mosul.
The United Nations said Friday at least 55,000 people had fled Ramadi alone since mid-May.
President Barack Obama has 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.
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."
In Palmyra, at a strategic crossroads between Damascus and the Iraqi border to the east, IS executed at least 17 suspected loyalists of the Damascus government Thursday, the Syrian Observatory for Human Rights said.
- Priest kidnapped -
IS proclaimed Palmyra's capture online and posted video and footage of its fighters in the city's air base, but not of the UNESCO world heritage site's colonnaded streets, elaborately decorated tombs and temples.
Syria's antiquities director Mamoun Abdulkarim urged the world to "mobilise" to save the treasures.
Also on Thursday, a Syrian priest and his colleague were kidnapped from a monastery between Homs and Palmyra, the French NGO L'Oeuvre d'Orient said.
Father Jacques Mourad was preparing aid for an influx of refugees from Palmyra and was known to help both Christians and Muslims.
IS now controls "more than 95,000 square kilometres (38,000 square miles) in Syria, which is 50 percent of the country's territory," the Observatory said.
Fabrice Balanche, a French expert on Syria, said "IS now dominates central Syria, a crossroads of primary importance" that could allow it to advance towards the capital and third city Homs.
Matthew Henman, head of IHS Jane's Terrorism and Insurgency Centre, said the jihadist advance "reinforces IS's position as the single opposition group that controls the most territory in Syria".
AFP
