DAMASCUS — Syrian government forces backed by Lebanon’s Hizbullah took control of a town just outside Damascus from Islamist fighters on Thursday, a blow to the rebels who had held it for more than a year.

Syrian state television broadcast showed government soldiers in the streets of Mleiha, which lies on the edge of the eastern Ghouta region near Damascus airport and had been surrounded by President Bashar al-Assad’s forces. Buildings were damaged or reduced to rubble, and tanks patrolled the streets.

Mleiha, about 7 km (4 miles) from the heart of Damascus, has formed a base for rebel fighters to bombard the capital with mortars in Syria’s three-year-old civil war.

The Britain-based, pro-opposition Syrian Observatory for Human Rights said government warplanes attacked several areas in the town. A Syrian rebel source said government forces had taken most of Mleiha and were using planes to attack the last point of resistance. Some of the rebels pulled out to nearby villages.

“Everything here is now under the control of the Syrian Arab Army,” a soldier standing near a damaged building told state TV.

“The town of Mleiha is the biggest in Ghouta and used to be a supply route for the gunmen. This will lead to the fall of other towns into the hands of the army,” said an army commander.

Government forces have pushed back the rebels around Damascus with help from Hizbullah and consolidated Assad’s grip over central Syria and along the border with Lebanon.

The Syrian army has nearly encircled Aleppo, preparing a siege to wrest control of the city from rebels in what would be the biggest blow yet to the three-year uprising.

The fall of Aleppo, Syria’s largest city and economic hub before the fighting, could also bolster the ranks of Islamic State militants who continue to make gains across the country, as defeated members of the Western-backed Free Syrian Army switch to their side.

Rebel commanders in Aleppo say they are stockpiling goods as aid groups step up food deliveries—crates of lentils, rice, ketchup and baby formula—seeking to prevent the same kind of mass starvation that forced them to surrender the much smaller city of Homs in May.