Syria's army have recaptured the only Golan Heights crossing on the ceasefire line with Israel, in another setback for rebels a day after they were forced out of the strategic town of Qusayr.
Austria, meanwhile, yesterday said it was withdrawing its troops from a UN peacekeeping force on the Golan because of the deteriorating security.
Qusayr's capture gives President Bashar al-Assad the upper hand if a US-Russian plan for the first direct peace talks with his opponents materialises, analysts say.
Russia said Syrian Foreign Minister Walid Muallem would lead a government delegation at the "Geneva 2" talks which have been delayed largely over opposition disputes about who will attend.
The rebels briefly took control of the Quneitra crossing, strategically and symbolically important for its proximity to Israeli forces and to Damascus, before being forced out.
An AFP correspondent said he could see tanks inside the area after Assad's troops moved back in yesterday.
Both the Syrian Observatory for Human Rights and Israeli army radio said the rebel advance had included fierce fighting in nearby Quneitra town.
The clashes were very close to the headquarters of a UN peacekeeping force, prompting Austria to announce it was withdrawing its troops and throwing the mission into disarray.
Two peacekeepers, from India and the Philippines, suffered "minor injuries" in shelling, a UN peacekeeping spokesperson said.
In Vienna, the government said the threat to Austrian soldiers "has reached an unacceptable level."
The Quneitra crossing, the only direct passage between Israel and Syria, is used almost exclusively by Druze residents of the Golan who are allowed to cross to study, work or get married.
