America’s hidden agenda in Syria’s war
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.
The commander - a moderate Sunni and an influential rebel leader from Damascus who said he has met intelligence operatives from Western and Arab states - said the US officials were especially keen to obtain information about the identities of Al Nusra insurgents and the locations of their bases.
Then, by the rebel commander's account, the discussion took an unexpected turn.
The Americans began discussing the possibility of drone strikes on Al Nusra camps inside Syria and tried to enlist the rebels to fight their fellow insurgents.
"The US intelligence officer said, 'We can train 30 of your fighters a month, and we want you to fight Al Nusra'," the rebel commander recalled.
Opposition forces should be uniting against Mr Al Assad's more powerful and better-equipped army, not waging war among themselves, the rebel commander replied. The response from a senior US intelligence officer was blunt.
"I'm not going to lie to you. We'd prefer you fight Al Nusra now, and then fight Assad's army. You should kill these Nusra people. We'll do it if you don't," the rebel leader quoted the officer as saying.
What the commander says transpired in Jordan illustrates a dilemma that has preoccupied, even paralysed, Syria's opposition and their international supporters - how to deal with the expanding role of Islamic extremists in the anti-Assad insurgency.
Other meetings with Western and Arab intelligence services have shown a similar obsession with Al Nusra, the commander said.
"All anyone wants is hard information about Al Nusra, it seems to be all they are really interested in. It's the most valuable commodity you can have when dealing with these intelligence agencies," he said.
Jabhat Al Nusra has emerged as the most effective rebel force in Syria. The fractured, poorly equipped rebels of the Free Syrian Army can ill-afford to take the fight to Mr Al Assad's forces without Al Nusra, whose key leaders are foreign veterans of the fighting that followed the US invasion of Iraq in 2003.
The Obama administration classified Al Nusra as a terrorist organisation in December, much to the annoyance of the opposition Syrian National Coalition (SNC), which said the designation would only undermine the rebel campaign and support Mr Al Assad's insistence that he is fighting "terrorists" rather than a popular, pro-democracy uprising.
Two months ago, Al Nusra confirmed its link to Al Qaeda, publicly declaring "allegiance" to the network's head, Ayman Al Zawahiri, and promised to follow his orders.
Ever since, opposition political and military leaders, and their supporters in Europe, the US and the Middle East, have been trying to work out how to deal with the fact their allies on the battlefield are affiliated with the group that carried out some of world's deadliest attacks on civilians.
As the rebels and their patrons abroad debate how to deal with Al Nusra, questions persist over exactly how united Al Nusra is, and whether or not it has adopted a new, less violent, strategy than that normally associated with Al Qaeda.
While key Al Nusra leaders are foreign fighters bloodied in Iraq's sectarian civil war, a majority of the group's rank-and-file are Syrians, some of whom have expressed dismay about the pledge to Al Qaeda.