Syrian forces have captured the largest town in Eastern Ghouta, effectively splitting the rebel-held enclave in three, a monitor told.
The Syrian Observatory for Human Rights (SOHR) said on Saturday that government forces had captured the town of Mesraba, which lies 10km east of Damascus, and had begun advancing into its surrounding farms.
The UK-based monitor told that Eastern Ghouta had been divided into three parts - Douma and its surroundings, Harasta in the west, and the rest of the towns further south.
Syrian state television reported earlier that army operations were intensifying in the central part of Eastern Ghouta, with opposition activists also reporting that roads connecting the towns were covered by army fire.
The Syrian American Medical Society (SAMS) told that at least 49 people, including 14 women and 10 children were killed on Friday, and a further 200 wounded.
President Bashar al-Assad and Russia say the campaign is needed to end rebel rule over the area's civilians.
Aid agencies have struggled to deliver aid to the besieged enclave, bringing in only a portion of the amount they wanted.
The Syrian government's offensive follows a pattern of previous assaults on rebel strongholds, deploying massive air power and tight sieges to force rebel fighters to accept "evacuation" deals.
These involve rebels surrendering territory in exchange for safe passage to opposition areas in northwest Syria, along with their families and other civilians who do not want to come back under Assad's rule.