It was some six months ago that Syrian rebel commanders met US intelligence officers in Jordan to discuss the status of the war and, the rebels hoped, to secure supplies of the sophisticated weapons they need to overthrow President Bashar Al Assad.

But according to one of the commanders present at the meeting, the Americans were more interested in talking about Jabhat Al Nusra, the Al Qaeda-affiliated group waging war on the Syrian regime than they were in helping the rebels advance on Damascus.