SAHEL, Syria — Syrian government troops are tightening their grip on the last rebel stronghold near the border with Lebanon a day after taking control of a key village in the area, a field commander told reporters on Tuesday.

Forces loyal to President Bashar Assad have seized a string of towns and villages in the rugged Qalamoun region along the Lebanese border since launching an offensive there in November. Backed by gunmen from the Lebanese militant Hezbollah group, the army seized the village of Sahel this week and is closing in on Yabroud, the largest town in the mountainous region still in rebel hands.

The government operation aims to sever the rebel supply routes from nearby Lebanon and shore up its hold on the main north-south highway that runs through the area.

During a government-led tour of the village of Sahel, a Syrian commander told reporters that troops ousted opposition fighters from the village Monday, bringing down the rebels’ “first defense line” of Yabroud. The officer did not provide his name, in line with military regulations.

Hezbollah guerrillas have played a significant role in the government push. The Lebanese Shiite militia is eager to clear the border area of the overwhelmingly Sunni Muslim rebels trying to topple Assad’s government. Hezbollah claims that several cars used in recent bombings targeting predominantly Shiite neighborhoods of south Beirut have been rigged in Yabroud. Al-Qaida-linked groups have claimed responsibility for several of the attacks in Lebanon, saying they were retaliation for Hezbollah’s military support for Assad.

Opposition groups said fighting was raging Tuesday on the edge of Yabroud, with government helicopters dropping barrel bombs on the town’s outskirts. The makeshift bombs are packed with explosives and fuel and are intended to cause massive damage to urban areas.