Eastern Ghouta's 400,000 inhabitants have lived under government siege since 2013 and the enclave - more than half of which has over the past three weeks been retaken by government forces - is home to numerous armed groups.
The cease-fire endorsed more than a week ago by the United Nations Security Council - but not yet implemented - does not cover H.T.S., a coalition of rebel forces led by the Nusra Front, a group that was formed as Al Qaeda's Syria affiliate and is listed internationally as a terrorist group.
The government, determined to wrest the eastern Ghouta suburbs from the control of rebels after seven years of war, has intensified the shelling and bombardment to clear the way for its troops to advance on the ground.
Jaish al-Islam is one of the main insurgent factions in eastern Ghouta.
Regime fighters cut off a road linking Douma with the town of Harasta further west and also captured the town of Misraba, according to the Syrian Observatory for Human Rights. "So Ghouta will gain by finishing with these people".
However, UN agencies said most medical supplies had been stripped from the convoy by Syrian government officials and added that the food supplies brought in were insufficient.More news: Aldon Smith Surrenders To Sfpd After Allegations Of Domestic Violence
A clear strategy of the Syrian government's offensive in Eastern Ghouta has been to divide the enclave into isolated sections and so cut off rebel support and supply networks, the BBC's Arab Affairs editor Sebastian Usher says - and now the government appears to have all but achieved that goal.
On Friday, 13 HTS members and their relatives were bussed out of the enclave.
The ferocious three-week assault on the last major rebel stronghold near Damascus has captured about half its area and killed 960 people, according to a war monitor. Any solution to the crisis will probably involve a partial evacuation of rebel fighters and perhaps civilians, in a deal similar to past surrender agreements between the government and rebels.
Russian Federation has intervened on Assad's behalf while Turkey has backed rebels against his regime, rival militants and Kurdish forces.
Elsewhere in Syria, the White Helmets rescue force suffered its first female fatality on Saturday, after air strikes hit a rebel-held town in Idlib province.