Eastern Ghouta was emptied of rebels after a almost two-month deadly assault on the enclave and several Russia-brokered deals that saw tens of thousands of people transported on buses to Syria's north.
This video was shared by pro-regime media and is described as showing heavy bombardment hitting al-Hajar al-Aswad and Yarmouk Camp in south Damascus.
The development heralds another advance for President Bashar al-Assad's push to retake remaining enclaves and strengthen his position around the capital after retaking eastern Ghouta this month.
Chemical weapons inspectors collected samples from Douma on Saturday, two weeks after the suspected gas attack there prompted retaliatory strikes by Western powers on the Syrian government's chemical facilities.
Rebels on Thursday began pulling out of Dumayr, an enclave northeast of Damascus, under a surrender deal with the government.
Physicians for Human Rights, a US-based rights group, voiced "grave concern" over reports that Douma hospital staff had faced "extreme intimidation" after the area came back under government control to stop them talking about the incident.
State TV said 3,200 militants and their families were expected to leave the area in preparation for them to be transported to Idlib and Jarablus, a rebel-held territory at the border with Turkey.
The Syrian government and its ally Russian Federation denied responsibility for the suspected chemical attack.
The station said the evacuations would continue for three days.
In parallel with the implementation of the agreement in Eastern Qalamoun, units of the Syrian Arab Army are carrying out a military operation to eradicate the dens of terrorist organizations positioned in the south of Damascus as part of the ongoing war to combat terrorism in Damascus and its countryside.
On Sunday, Sweden's Ambassador to the United Nations said that he and other Security Council envoys had agreed to work on a "meaningful mechanism" to work out who was behind the alleged use of chemical weapons in Syria.
The goal of the attack was to recapture Batra Mountain alongside Al-Nassiriyah.