BEIRUT – Syrian troops ambushed a large group of rebels Wednesday trudging what once was a secret route through a desert road northeast of Damascus, killing more than 60 fighters in a barrage of machine gun fire and leaving their bodies in the sand.

State television claimed those killed came from an al-Qaida-linked group that has joined the battle against President Bashar Assad, whose troops are trying to drive opposition forces from areas surrounding his seat of power in the capital.

There were conflicting reports on the attack in Adra, which lies on a supply route between Damascus and rebel-held areas to the east that is often the scene of heavy clashes between the two sides. The dawn attack dealt another heavy blow to opposition troops following a string of recent regime successes.

Syrian troops have been on the offensive in the past few months in an attempt to clear out Damascus suburbs held by opposition fighters.

Syrian state-run media showed footage of bloodied corpses lying on the ground, some wearing camouflage gear with their weapons scattered around in the sand. One picture showed gas masks next to the weapons.

The state-run SANA news agency said “dozens” of rebels were killed in the ambush as they were on their way to attack an army post near Damascus. SANA identified the dead as members of the al-Qaida-linked Jabhat al-Nusra, and said some were foreign fighters.

Syria’s crisis started as a largely peaceful uprising against Assad’s rule in March 2011. It turned into a civil war after opposition supporters took up arms to fight a brutal government crackdown. More than 100,000 people have been killed.

The scale of that destruction could be seen in satellite images released Wednesday by Amnesty International. The images showed hundreds of damaged or destroyed houses and more than 1,000 roadblocks around the northern city of Aleppo, which has seen months of vicious fighting.

“Satellite images really speak for themselves,” said Donetella Rovera, a senior Amnesty adviser. “You can see really clearly buildings — groups of buildings — that were there a year ago that are no longer there today.”