Shelling killed at least 13 people today in the Damascus district of Qaboon, where fierce fighting between the army and rebels has trapped hundreds of families, a monitor said.
The Syrian Observatory for Human Rights also reported a car bomb detonated outside a police station in Damascus province, causing an unknown number of casualties.
"The toll from shelling on Qaboon rose to 13 people," the Observatory said, adding three civilians and seven rebels were among the dead, and that three bodies had not yet been identified.
The deaths came after the Observatory warned that hundreds of families were trapped in the northeastern district by fierce fighting between troops and rebel fighters.
"There is a siege because regime snipers are posted on the outskirts of Qaboon and this makes any attempt to leave difficult," said the group. "The area has also been bombed by the army."
Regime troops have been trying for months to dislodge rebels from rear-bases they have established in parts of the outskirts of Damascus.
Footage filmed by activists in Qaboon showed smoke rising from the area as the sound of non-stop artillery and mortar fire rings out.
The Observatory said residents of the area were facing a "stifling" siege.
"There's a major shortage of food and some families have nothing to feed their children with," it said.
The Observatory also reported that dozens of people detained in an underground makeshift prison near a mosque in Qaboon escaped when regime forces guarding the site left to join the fighting.
Overnight, the opposition National Coalition had urged the international community to act to free "200 people" they say are being held in the mosque.
Rebels fighting to overthrow President Bashar al-Assad's government control several neighbourhoods on the outskirts of Damascus from which they are able to shell areas in the city centre, which is still in regime control.
Forces loyal to Assad have for months been trying to uproot those rear-bases, including in Qaboon and Barzeh, in northern Damascus.
Nearby, in Damascus province, the Observatory reported a car bomb detonated outside a police station in the town of Deir al-Attiya.
