Fresh fighting erupted on the outskirts of Damascus on Friday, as Syrian regime troops battled rebels in the north, south and east, backed in some areas by tanks and militia, a watchdog said.
"Fierce clashes are raging in Barzeh district, pitting rebels against troops and members of the pro-regime popular committees," the Syrian Observatory for Human Rights said.
The district in northern Damascus also came under tank fire by the army, the British-based group said.
The militiamen were brought in from Esh al-Warwar district, which has a population drawn mainly from the Alawite minority community to which President Bashar al-Assad belongs, it added.
Most of the rebels are from Syria's Sunni Muslim majority.
In its third year, the conflict has taken on an increasingly sectarian nature, as Assad's regime has armed militias among the Alawites and other minority groups.
Analysts say the militias have better knowledge of the ground and are more adept at street fighting than the regular army, which is largely made up of conscripts.
Rebels and troops also clashed in several areas of south Damascus, parts of which have been reduced to rubble by months of fighting.
In the east of the capital, fresh fighting erupted in Jubar district, where rebels hold a number of enclaves, the Observatory said.
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The army also shelled the eastern suburbs, where rebels have established rear bases they have used to launch attacks deeper inside the capital.
Warplanes, meanwhile, bombarded Ain Terma, east of Damascus, and Daraa to the southwest, the Observatory reported.
Regime forces launched a campaign several months ago to crush the insurgency near Damascus and to secure the capital.
Activists say civilians are paying the highest price for the violence near and around Damascus.
Thousands of people, among them women and children, are holed up in rebel stronghold Moadamiyet al-Sham, close to the town of Daraya, an activist with close ties to anti-regime networks in Damascus province said.
"There is daily bombardment, and thousands of residents in Moadamiyet al-Sham are under siege by the army. There is no bread, no baby formula for children. People are eating rotten bread," the activist, who identified himself as Malek, told AFP.
Elsewhere, jihadist rebels planted explosives targeting troops on a strategic road used by the army to send reinforcements and supplies towards eastern Aleppo, the Observatory said, adding that the attacks had killed an unknown number of soldiers.
And in the northwestern province of Idlib, clashes raged around the Abu Al-Dohur airport, as rebels kept up a fierce campaign to take over air bases in insurgent-held areas in Syria.
At least 130 people died in violence across Syria on Thursday, the Observatory said -- 53 civilians, 27 soldiers and 50 rebels.