Negotiators in the last rebel-held bastion in Syria's Eastern Ghouta reached a deal with the Russian side to move the wounded from Douma to rebel-held northern Syria, local sources said.
The agreement was reached by the negotiating committee that comprises both civic leaders and representatives of Jaish Al Islam, the rebel faction in control of Douma, according to Reuters news agency.
Some 1,300 fighters, activists and civilians signed up to leave the town, according to the Syrian Observatory for Human Rights, based in Britain.
But while an agreement to evacuate wounded civilians was set in place late on Saturday, the fate of the rebel fighters remained unclear.
A council member of opposition-controlled Douma on Sunday denied earlier reports by the Syrian military media that the Jaish Al Islam faction had agreed to surrender the town to the regime.
The Central Military Media outlet, which is linked to the Syrian military, said that the rebel group had agreed to leave Douma for Jarablus, a town shared between rebel and Turkish control in northern Syria.
Council member Yad Abdelaziz said there was no such agreement in place, but that "humanitarian cases" would be allowed to evacuate on Monday.
Hundreds of residents are believed to require care for war wounds and medical conditions exacerbated by the siege. The government routinely blocks aid groups from evacuating patients from besieged areas for medical care.
An opposition official told Al Arabiya television that the Jaish Al Islam was still engaged in talks with Russia over the future of Douma.
Ahmad Ramadan said that Turkey, which backs various Syrian rebel groups, and shares control over a part of opposition territory in north Syria, is also party to the talks.
The committee has been working on a deal to spare the city an assault by the encircling Syrian army and its allies.
They threatened to storm the city if rebels did not surrender the last ground in the enclave in return for safe passage to insurgent-held territory.
The Syrian army's efforts to recapture the area have been some of the most intense in the seven-year war.
After helping to turn the tide of the war in President Bashar Al Assad's favour with air power and military support since its intervention in 2015, Russia has increasingly cast itself as a peace-broker. Russian representatives have played a role in negotiating local ceasefires and evacuations.
Mr Al Assad and his allies say their offensive in Eastern Ghouta is necessary to end the rule of militants over the area's people, and to stop them shelling government areas.
People in besieged Eastern Ghouta have suffered shortages of food and medicine, and during the weeks-long battle they were often unable to leave their homes to bury the dead.
Tens of thousands of people have left Eastern Ghouta in recent weeks, although many civilians remain.
Douma was one of the earliest hubs of the uprising against Mr Al Assad in 2011. The security services responded by putting the town and other suburbs around Damascus under siege, bombing hospitals and residential areas, and blocking food and medical relief. Douma is one of the last pockets of the opposition around the capital to hold out against the government.
The Observatory monitoring group reported earlier in the day on Sunday that Russia's military police would be deployed inside Douma to take custodianship of the town.