Syrian rebels launched a major offensive on Sunday that brought them close to the heart of the Old City of Damascus, and government forces responded with intense bombardments of rebel-held areas.
State television reported that government forces have "tightened the noose around terrorist groups besieged in the industrial zone on the northern edges of Jobar".
Witnesses said the army deployed tanks in some adjacent neighborhoods, and troops could be seen patrolling on foot.
Smoke billows following a reported air strike in the rebel-held parts of the Jobar district, on the eastern outskirts of the Syrian capital Damascus, March 19, 2017.
The insurgents detonated two suicide vehicle bombs in Jobar district before trying to storm government defence lines, observers said.
Steady shelling and sniper fire could be heard across Damascus on Sunday as rebel factions allied with former Al-Qaeda affiliate Jabhat Fateh al-Sham launched an attack on government positions in the city's east. The ultraconservative Ahrar al-Sham rebel group claimed victory, Al Jazeera said.
The Observatory said rebel shells hit several nearby districts in Damascus, including Bab Touma, Rukn al-Din and the Abbasiyin area.
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Insurgent groups attacked government positions in the area, including with two auto bombs, in an attempt to storm their defence lines, the Britain-based Observatory said.
SOHR chief Rami Abdel Rahman said the rebels were seeking to "link their territory in Jobar with Qabun to break the government siege there".
"Taking this road would isolate Barza and Qaboun completely and with a security belt around it", said Abu Abdullah, another fighter with Failaq al Rahman.
Infantry and tank reinforcements arrived on the government side to repel the attack in the afternoon, the group said. The fighting targeted the government-controlled gap between Jobar and Qaboun. The evacuations are expected to continue for weeks, until the government will be able to claim control over the entire city for the first time since demonstrations broke out against President Bashar Assad in 2011.
Another rebel fighter acknowledged army advances towards a major road between Qaboun and Barza.
The army and its alliliated militias have been targeting the besieged Eastern Ghouta area, the biggest remaining rebel bastion around the capital, for months, making incremental gains.