The fighting at Taftanaz underscores the growing influence in the rebel movement of conservative Islamic groups such as Nusra, which has grown in the space of little more than a year from a small clandestine organization that largely carried out bombings into a group that fields battalions of fighters across the country.
A recent report by the Quilliam Foundation in the United Kingdom estimated that Nusra now has about 5,000 fighters. Rebel supporters point out that that’s only about 10 percent of the anti-Assad forces, but given the fractured nature of the movement, that number of fighters probably means that Nusra is among its largest fighting organizations.
Rami Abdurrahman, the director of the Syrian Observatory for Human Rights, which tracks the violence in Syria, said he thought Nusra made up “30 to 40 percent” of the rebels’ effective fighting force. “Some groups work in some areas, and you think they are different groups, and they are actually part of Jabhat al Nusra,” said Abdurrahman, whose organization is considered the primary authority on the daily violence in Syria.
“They are getting bigger every day,” he added.
Analysts said the fighting prowess of Nusra and Ahrar al Sham was owed in part to the presence in their ranks of Syrians and Iraqis who fought the U.S. military and the Iraqi government during the U.S. occupation of Iraq, which ended in December 2011. In addition to their attacks on air bases, Nusra and Ahrar al Sham are leading the fighting in cities along Syria’s main north-south highway. Refugees fleeing violence in Damascus also said Nusra was at the forefront of fighting in that city’s Yarmouk district.
The highly visible successes of groups such as Nusra, which say they’re funded by individual donors from Syria and Persian Gulf countries such as Qatar and Saudi Arabia, have allowed them to add to their ranks. The fact that they’re often at the forefront of the fighting also has allowed them to capture weapons when they overrun military positions. Recent videos have shown the groups effectively using tanks and armored personnel carriers captured from government troops.
The rebels were likely also to have benefited in recent days from a fierce snow and rain storm in the region that’s prevented the Syrian government from using aircraft for much of the last four days. Rebels said the government instead had attempted to use surface-to-surface missiles to attack them at the base and to destroy equipment that they might capture.
Hannah Allam contributed to this article from Washington.