ISIS cements grip on Iraq-Syria border

Damascus - 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 sparked criticism of US military strategy in the region.

A suicide bomber from the extremist Sunni organisation also attacked a Shi'ite mosque in Saudi Arabia, raising sectarian tensions.

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 on Thursday.

Raised fears

It was the last regime-held border crossing with Iraq.

The jihadist surge, which has also seen it take Ramadi, capital of Anbar province, 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 ISIS will repeat at Palmyra the destruction it has already wreaked at ancient sites in Iraq's Nimrud and Mosul.

The United Nations said at least 55 000 people had fled Ramadi alone since mid-May, while the Security Council voiced "grave concern" for Palmyra as well as civilians trapped there.

President Barack Obama has played down the ISIS advance as a tactical "setback" and denied the US-led coalition was "losing" to ISIS.

Human civilisation

The Pentagon said coalition aircraft launched five strikes against ISIS in Syria and 15 against the jihadists in Iraq in the past 24 hours.

Unesco chief Irina Bokova called the 1st and 2nd Century Palmyra 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."