Syrian troops battered rebel positions in and around Damascus in an assault aimed at securing the capital, as Russia and Turkey are in talks in Istanbul on Monday on their differences over the conflict.
Syrian Observatory for Human Rights said artillery gunners targeted districts of Hajar al-Aswad and Tadamun as well as the Palestinian refugee camp of Yarmuk in southern Damascus.
The army also bombarded Yabrud, Yalda to the south and the Eastern Ghouta towns of Douma, Harasta, Irbin and Haran al-Hawamid, in the area of the road linking Damascus to its international airport, it said.
Forces loyal to President Bashar al-Assad have been trying to establish a secure perimeter around Damascus at all costs, turning the province into one of the main battlegrounds in the country's 20-month conflict.
Analysts say the objective of the military campaign is to put the regime in a position to negotiate a way out of the conflict that the Observatory says has cost more than 41,000 lives since March 2011.
Russian President Vladimir Putin, meanwhile, was to meet with Turkish Prime Minister Recep Tayyip Erdogan to discuss their differences on Syria.
The talks will cover reconciliation in Middle East, the situation in the Gaza Strip, the crisis in Syria.