Syrian troops on Tuesday captured the village of Qara in the mountainous Qalamoun region along a key supply route between Damascus and Homs, a military source told AFP.
The reported capture came after days of air strikes on the region near the Lebanese border, which is also a key smuggling route for rebels battling to oust Syrian President Bashar al-Assad.
"After three days of fighting, the Syrian army has taken full control of Qara," some 100 kilometers (60 miles) north of the capital, the Syrian military source said, adding that a "large number of terrorists" had been killed, referring to the rebels.
The fighting in Qara sent at least 1,700 people streaming 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.
On Tuesday a double suicide bombing targeting the Iranian embassy in Beirut and claimed by Sunni Muslim jihadists ripped through a Shiite neighborhood.
Iran is a key ally of Damascus, and the powerful Lebanese Shiite movement Hezbollah has sent fighters to battle alongside Assad's troops, including in Qalamoun.
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 neighboring states like Lebanon and Iraq.
The uprising against Assad began in March 2011 as peaceful pro-democracy protests but escalated into a full-blown insurgency after a brutal government crackdown.
The fighting has taken on an increasingly sectarian character, with Shiite militants from Lebanon and Iraq fighting alongside regime troops and al-Qaeda-inspired jihadists flooding into the country to join the Sunni-led rebels.
Lebanon's factions are bitterly divided over the Syrian war, with Sunnis backing the rebels while Hezbollah and its allies support Assad.