Syrian troops backed by Lebanese Hezbollah fighters and other pro-regime militia have retaken a major rebel enclave south of Damascus, severing a key opposition supply line.
The recapture, reported by a monitoring group and state television, was part of a broader army campaign that has seen a string of towns in the area fall into regime hands.
Meanwhile, US Secretary of State John Kerry said in Amman he believed peace talks that had been proposed for the end of November could still be held in the coming weeks.
And in The Hague, the Organisation for the Prohibition of Chemical Weapons (OPCW) said inspectors had verified all but one of Syria's 23 declared chemical weapons sites.
The regime's recapture of Sbeineh comes nine days into a campaign aimed at cutting off one of the main rebel supply lines into southern Damascus, said the Syrian Observatory for Human Rights.
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The Britain-based monitor said Sbeineh is one of the most important rebel position on the edges of Damascus.
"Rebels in southern Damascus have now had practically all their supply routes cut off," said Observatory chief Rami Abdel Rahman.
He said troops were backed "by fighters from Hezbollah," the powerful Lebanese Shi'ite movement, as well as "Syrian and non-Syrian Shi'ite fighters."
They have besieged a number of rebel-held suburbs, and UN officials have expressed concern over reports of trapped civilians and severe malnutrition.
"There are fears for the lives of civilians in Sbeineh. Experience tells us that the army may well execute civilians and put the blame on rebels," said Abdel Rahman.
Syrian state television said "terrorists" - the regime's term for rebels - were crushed in Sbeineh.
Abdel Rahman said the army has been able to advance in part because of "divisions among the rebels."
The OPCW say its inspectors had verified all but one of Syria's declared chemical sites.
The group said Syrian personnel had visited one of two remaining sites that they could not visit for security reasons and filmed it with "sealed cameras."
OPCW and UN inspectors have until mid-2014 to destroy Syria's entire chemical arsenal and production facilities under the terms of a US-Russian deal to head off military strikes on Assad's regime.
