Elite Syrian regime forces stationed at Mazzeh military airbase shelled the embattled town of Daraya just southwest of Damascus on Sunday, opposition activists and a watchdog reported.
"Heavy artillery and tank shelling hit Daraya from Mazzeh military airport and the Fourth Division headquarters on Moadamiyet mountain as fierce explosions shook the town," the Syrian Revolution General Council said.
The Syrian Observatory for Human Rights also reported the bombardment.
Daraya has been the scene of a fierce regime onslaught with tank fire and air raids for more than two months as troops loyal to President Bashar al-Assad seek to retake the beleaguered rebel bastion.
State news agency SANA reported late on Saturday that "our valiant army continued to pursue armed terrorist groups who had carried out killings and theft and targeted the infrastructure of Daraya."
An anti-regime activist living in the town told AFP that 90 percent of the residents had fled in late November amid escalating attacks and the arrival of elite Republican Guard troops.
Overnight, the Britain-based Observatory said nine people were wounded in a car bombing in Jaramana, a majority Christian and Druze district southeast of Damascus where more than 50 people were killed in car bombings last November.
The watchdog also reported fierce clashes between troops and rebels near an air force administration building in the nearby town of Maliha on Sunday.
For months, rebels and troops have battled where insurgents have set up rear bases outside the capital.
The Assad regime has regularly claimed to be launching its final crackdown on the insurgency in Damascus province.