Fierce fighting and clashes between regime forces and rebels rocked the eastern edge of Syria's capital on Friday, an AFP correspondent and military source said, despite a fragile truce across the country.
"The Syrian army is blocking an attack by armed groups that tried to enter the capital's east via Jobar... leading to intense clashes and rocket fire," a military source told AFP.
A barrage of rocket fire and shelling could be heard coming from the Jobar district, a rebel-held eastern suburb of Damascus.
The district has been a battleground for more than two years and nearly all of its pre-war population has fled.
The Syrian Observatory for Human Rights monitoring group also reported the clashes and said more than 21 shells and rockets hit parts of Jobar.
Two shells also hit the Bab al-Sharqi neighbourhood of Damascus but did not result in any casualties, the Observatory said.
Rami Abdel Rahman, who heads the Britain-based monitor, said both Islamist faction Faylaq al-Sham and the Fateh al-Sham Front -- formerly Al-Qaeda's Syrian affiliate -- were present in Jobar.
He did not have immediate information on casualties.
Under the truce deal negotiated by Moscow and Washington, which came into force on Monday evening, fighting is to halt across the country except in areas where Islamist militants are present.
Observers have noted that the deal will be particularly difficult to implement in areas where Fateh al-Sham has formed strong alliances with local rebels.