Under pressure from fellow insurgents and escalating airstrikes by the US-led coalition, Syria's al-Qaida branch is stepping up violence against President Bashar Assad's strongholds with precise, high-profile attacks, including a surprising breach of the capital in the most serious infiltration in years.
Sunday's attack, in which insurgents used tunnels they control in northeastern Damascus neighborhoods to hit government positions, appears to have caught the Syrian military off guard.
It was a grim reminder that the fighting is far from over, despite significant advances by Assad's forces against rebels across the country in the past year.
The government dispatched some of its elite forces to halt the offensive, which began shortly before sunrise with two suicide bombers from an al-Qaida-linked group.
The bombers, a Saudi and a Syrian, detonated their explosives-laden trucks against army positions on the eastern edge of the capital amid a barrage of artillery shells that landed in the heart of Damascus.
Dozens of insurgents penetrated the city's defenses and captured several blocks northeast of Damascus, triggering fierce clashes that lasted for hours before the fighters were pushed back to where they started.
Insurgent groups repeatedly have tried to break Damascus' defenses in recent years. Syria's al-Qaida's branch has used suicide bombers targeting government security installations since the early days of the conflict.
Sunday's incursion, however, was the most serious since 2012, when rebels captured several Damascus neighborhoods before being crushed by government forces. It was the latest in a series of stepped-up attacks claimed by the al-Qaida-linked Levant Liberation Committee.
The gains, though short-lived, came against the backdrop of months of steady rebel losses to government forces across the country.
It appeared to be an attempt by al-Qaida to mount sophisticated attacks against high-value targets to portray itself as the main force capable of fighting the government.
"Every time they can successfully carry out one of these, then it bolsters their case within the armed opposition," said Sam Heller, a Beirut fellow at the US-based Century Foundation.
The Levant Liberation Committee, the latest spinoff from Syria's al-Qaida branch, has claimed several other high-profile attacks in government-controlled areas recently.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)