Syrian army forces pushed deeper into the last rebel-held enclave near a strategic border area with Israel and Lebanon.
The army and the Shi‘ite forces advanced east and south of the Sunni-rebel held bastion of Beit Jin backed by some of the heaviest aerial bombing and heavy artillery shelling since a major assault began over two months ago to seize the area, rebels said.
The Syrian army said it had encircled the village of Mughr al Meer at the foothills of Mount Hermon as troops moved toward Beit Jin amid fierce clashes.
The enclave is the last rebel bastion left in the south west of Damascus known as the Western Ghouta that had since last year fallen under government control after months of heavy bombing on civilian areas and years of siege tactics that forced rebels to surrender.
The southwest of Syria is part of a de-escalation zone in southern Syria agreed last July between Russia and Washington, the first such understanding between the two powers.
The area has not seen Russian bombing unlike other ceasefire areas in Syria.
Diplomatic sources say several thousand Shi‘ite fighters who have been amassing from outside the Quneitra province are pitted against hundreds of Islamist and mainstream Free Syria Army (FSA) rebels closing ranks under the banner of Itihad Quwt Jabal al Sheikh “Union of fighters of Jabal al Sheikh”. They are mainly drawn from local fighters from the area.