Heavy clashes rocked eastern districts of the Syrian capital on Sunday as rebels and terrorist outfits tried to fight their way into the city centre in a surprise assault on government forces.
The attack comes just days before a fresh round of UN-brokered peace talks in Geneva aiming at ending Syria's six-year war.
Rebels and government forces agreed to a nationwide cessation of hostilities in December, but fighting has continued across much of the country, including in the capital.
Steady shelling and sniper fire could be heard across Damascus as rebel factions allied with former Al-Qaeda affiliate Fateh al-Sham Front launched an attack on regime positions in the east of the city.
The attack began early in the day "with two car bombs and several suicide attackers" in the Jobar district, said Rami Abdel Rahman, head of the Syrian Observatory for Human Rights monitoring group.
Rebels seized several buildings in Jobar and advanced into the nearby Abbasid Square area, seizing part of a large bus station and firing a barrage of rockets into multiple neighbourhoods, Abdel Rahman said.
Regime warplanes have targeted rebel positions with more than 30 air strikes since the morning, he added.