Syria's army command on Saturday announced that the eastern Ghouta region was free of militants, following the departure of the last rebel fighters from the city of Douma towards the north of the country, state media reported, citing a statement by the Syrian army general command.
"All the terrorists have left Douma city, their last bastion in eastern Ghouta," the statement said.
On Sunday, the Jaish al-Islam rebel group, which had controlled the city, reached an agreement with the government and its Russian military allies to leave the city shortly after an alleged chemical attack on April 7 that killed dozens of civilians.
The attack prompted a joint military operation by the United States, Britain and France that targeted several facilities near Damascus and the city of Homs on Saturday.
Buses carrying rebels and their families and civilians who did not wish to stay in Douma under President Bashar al-Assad's rule have left the city in batches over the past few days to travel to opposition-held areas in northern Syria, near the border with Turkey.
The government forces launched their offensive against eastern Ghouta in February, backed by Russian firepower.
The Syrian Observatory for Human rights, a British-based war monitoring group, says the campaign killed more than 1,600 civilians.
The conquest of Douma underlines how Russia's entry into the fray in 2015 on Assad's side has now helped him to an unassailable position in a conflict that mushroomed out of protests against his rule seven years ago.