BEIRUT — During a key battle in the rugged mountains of a northern province this month, U.S.-backed Syrian rebels collapsed before an assault by al-Qaeda fighters. Some surrendered their weapons. Others defected to the militants.
A detailed account of the battle in Idlib, from a series of interviews with opposition activists, underscores how the moderate rebels that Washington is trying to boost to fight the Islamic State group are instead hemorrhaging on multiple fronts.
They face an escalated assault by Islamic extremists, which activists say are increasingly working together to eliminate them. At the same time, a string of assassinations has targeted some of their most powerful commanders.
“This is the end of the Free Syrian Army,” said Alaa al-Deen, an opposition activist in Idlib, referring to Western-backed rebel groups. “It’s the beginning of an Islamic emirate.”
Thousands of rebels have died fighting the Islamic State this year, a war that has overshadowed and undermined the struggle to topple President Bashar al-Assad.
Now the Nusra Front — al-Qaeda’s branch in Syria, which previously was also fighting against the Islamic State group — has turned on more moderate factions.
Nusra’s pivot in part is in response to U.S. airstrikes, which have targeted the al-Qaeda branch in addition to Islamic State militants, several activists said.
In the fighting this month, the Nusra Front drove U.S.-backed factions almost completely out of the northwestern province of Idlib, where they had been the predominant force.
During the battles, two of the strongest Western-backed forces — the Hazm Movement and the Syrian Revolutionaries Front —were defeated, and several other allied groups simply vanished.
The Syrian Revolutionaries Front, headed by commander Jamal Maarouf, oversaw groups ranging from village-based militias to factions with hundreds of men. About 10,000 to 20,000 fighters are estimated to have been under his command.
