The Syrian government offensive aims to push rebels out of the Damascus area and firm up control around the capital. Observers have called it the biggest attack in Damascus in years.
The Syrian army attacked a Damascus suburb with rocket-fire on Sunday, continuing an attack that began a day earlier and has killed as many as 16 people.
The Syrian Observatory for Human Rights (SOHR), as well as a medical worker, called it the biggest attack on the capital's northeast suburb of Qaboun in more than two years. It also marked the highest death toll in the area since 2014.
Forces loyal to President Bashar al-Assad launched a total of 17 rockets on Qaboun, the SOHR reported. The head of SOHR, Rami Abdel Rahman, said both rebels loyal to the moderate Free Syrian Army and the radical militants of Hai'at Tahrir al-Sham (Levant Liberation Body) are present in Qaboun.
He added the shelling raises fear among residents of an imminent military operation in the area, as government forces try to drive opponents away from the Syrian capital.
Rebel shells hit Damascus
In an apparent retaliatory attack, at least three shells hit government-held areas near the center of Damascus, but so far there are no reports of casualties.
On Saturday, a government sniper killed one person in the area and rockets hit a cemetery on Qaboun's outskirts, said the medical worker, who asked not to be identified.
The British-based Observatory also reported attacks at a cemetery. The government did not immediately comment on the fighting in Damascus.
In nearby Eastern Ghouta, just outside Damascus, the medical worker said at least 13 people had died. He said he could hear explosions coming from Qaboun early on Sunday.
A shaky ceasefire is being further undermined by violence in western Syria. The ceasefire, which took effect on December 30, is supported by Syrian ally Russia and Turkey, which supports some rebel groups.
bik/sms (Reuters, dpa)