The Front for the Defence of the Syrian People has stated that there are jihadis who have returned from other wars to fight in Syria.
"The hard element of the opposition, the armed, the combat experience people, who come up either from Libya or Iraq, not only are at the vanguard, but they are actually pushing out all other forms of opposition," said Alistair Crooke is a former British intelligence officer.
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The regime blames the bombings in Damascus on Islamists.
But one Syrian fighter, who fought in Iraq, says al-Qaeda is not behind the bombings.
"The regime lies all the time, they even lie about the weather. The bombings are done by the regime," he told the BBC.
