World Bulletin / News Desk
"The incursion, which is backed by [pro-regime] militias, is massive," Tamam Abu al-Khair, a member of the Martyrs of Islam Brigade -- one of the most prominent opposition factions operating in Darayya said.
"Opposition defenses collapsed before the advance," he said.
"Regime forces have now entered residential areas [of Darraya] after establishing control over the western region, which was the area’s last line of defense," Abu al-Khair said.
"Now the regime is bringing in more reinforcements to consolidate its gains," he added. "It’s taking advantage of the state of calm currently prevailing in the country’s south."
Opposition groups are now voicing fear that the deployment in Darayya -- home to an estimated 8,000 people -- could suggest future violence against the area’s civilian residents.
In the summer of 2012, attacks by regime forces left some 800 civilian residents of the area dead, according to opposition sources.
Syria has been locked in a vicious civil war since early 2011, when the Assad regime cracked down on pro-democracy protests -- which had broken out as part of the "Arab Spring" uprisings -- with unexpected ferocity.
Since then, more than 250,000 people have been killed and more than 10 million displaced, according to UN figures.