Syria troops have captured the village of Qara in the mountainous Qalamoun region along a key supply route between Damascus and Homs.

The capture of the strategic area on Tuesday comes days after pro-Assad forces launched an offensive against the town near the Lebanese border.

"After three days of fighting, the Syrian army has taken full control of Qara," a Syrian military source told AFP news agency, adding that a "large number" of rebel fighters were killed.

State media SANA also quoted a military source as saying that the army "eliminated terrorists" last gatherings and destroyed their weapons".

There was no immediate comment from rebels, who use the region around Qara to cross over from Lebanon. But regional news channel Al Mayadeen broadcast images of a reporter walking with Syrian soldiers through Qara's empty streets.

The Syrian Observatory for Human Rights, a Britain-based monitoring group, said that the al-Nusra Front, a rebel group, had announced its withdrawal from Qara and "promised to be back soon".

The fighting in Qara, which is about 100km north of the capital, forced at least 1,700 families across the border into Lebanon, which is already hosting more than 800,000 Syrian refugees and has suffered from rising unrest linked to the Syrian conflict next door.

The UN refugee agency UNHCR estimates at least 6,000 people have fled to the Lebanese town of Arsal, near the border, since last Friday.

"Refugees have told us that they spent days living in underground shelters before deciding to flee," said Adrian Edwards, a spokesman for the UN refugee agency.

The Syrian civil war has claimed an estimated 120,000 lives and generated the biggest refugee crisis in two decades, raising fears that the conflict could spill over into volatile neighbouring states like Lebanon and Iraq.