Syrian troops stationed on a mountain overlooking Damascus fired artillery barrages late on Thursday at a southern neighbourhood of the capital, witnesses said.
The shelling took place hours after Syria's army command accepted a U.N.-proposed ceasefire due to being on Friday.
"Consecutive artillery volleys from Qasioun shook my home," said Omar, an engineer who lives in al-Muhajereen district on the foothill of the mountain.
The artillery barrage targeted Hajar al-Aswad, a poor neighbourhood inhabited by refugees from the Israeli-occupied Golan Heights. There were no immediate reports of casualties.
Rebels have been using the neighbourhood to launch operations against forces loyal to President Bashar al-Assad, several activists and residents of the capital said.
Security forces also conducted nightly house-to-house raids in the affluent Eastern Mezze Villas neighbourhood and arrested dozens of young men, after protesters blocked a main highway earlier with burning tires, opposition campaigners said.