State TV footage showed clouds of dark smoke rising from Douma as Syrian forces pushed into the town on Friday.
The Syrian army resumed airstrikes on the positions of militants in Douma following their violation of an evacuation agreement and their shelling of civilian areas earlier on Friday.
State news agency SANA reported that Jaish al-Islam terrorists, who are stationed in Douma, attacked al-Wafedin humanitarian corridor and al-Assad residential suburb in Harasta, causing civilian casualties.
Eastern Ghouta, which is home to nearly 400,000 people, fell to multiple militant groups in 2012, months after Syria plunged into crisis and has since served as a launch pad for fatal attacks against residents and infrastructure in Damascus.
The area has witnessed deadly violence over the past few months, with foreign-sponsored terrorists launching mortar attacks on the Syrian capital in the face of an imminent defeat.
After days of what has been described as one of the deadliest episodes in the war against foreign-backed militancy that has gripped Syria since 2011, Syrian forces agreed to let the militants flee to Syria's northern parts in order to save the lives of civilians caught in the crossfire.
Militant groups and their families have left different parts of Eastern Ghouta in convoys under deals with the government.
Eastern Ghouta has now been almost fully liberated with the exception of the town of Douma.
Recently, Moscow brokered an agreement between the militants based there and the Syrian government, enabling the former’s safe exit to Jarabulus, a militant-held town in northern Syria.
Russia said hundreds of militants and their families had left Douma according to the deal. But the terrorist group has sought to remain in the town as what it calls a local security force, the so-called Syrian Observatory for Human Rights said. The demand has been rejected.
A commander in the pro-government regional military alliance said the militants' only option was to quit the town.
"The negotiations have ended with failure. As far as Douma is concerned, resolving it militarily is the solution," the commander, whose name was not mentioned in the report, told Reuters on Friday.
State media outlets reported that Jaish al-Islam terrorists had obstructed the agreement and refused to release the abductees they have been holding in Douma.
The terrorists must "submit to the condition of the Syrian state: the abductees in exchange for a halt of the military operation", said a correspondent with state TV station al-Ikhbariya.