DAMASCUS, Syria — Syrian troops backed by Hezbollah fighters seized a key rebel supply town on the Lebanese border on Sunday, driving them from the area and scoring a major blow against them in the three-year-old-conflict.
The fall of Yabroud immediately emboldened government forces to attack nearby rebel-held towns, pressing forward in what has been nearly a yearlong advance against rebels fighting to overthrow President Bashar Assad.
Support from the Iranian-backed, Shiite Hezbollah appears to have tipped the balance in the border area, even as it has partly prompted the conflict to bleed into Lebanon where it has ignited polarizing sectarian tensions between Sunnis and Shiites.
In Lebanon, 13 people have been killed in Syria-related violence in recent days: 12 in gunbattles and one in a rocket attack. And in the capital, Hezbollah supporters celebrated Yabroud's fall with celebratory gunfire in Shiite-dominated areas, while youths on motorbikes waving the yellow Hezbollah flag noisily roared through the upscale central district.
Yabroud was an important supply line for rebels into Lebanon, and overlooks an important cross-country highway from Damascus to the central city of Homs. It the last major rebel-held town in the mountainous Qalamoun region, where Assad's forces have been waging an offensive for months to sever routes across the porous border. Its fall comes just a week after the Syrian army seized the village of Zara, another conduit for rebels from mountainous northern Lebanon into central Syria.
Syria's state television reported that military forces were removing booby-traps and bombs and hunting down rebel hold-outs in Yabroud.
"Our armed forces are now chasing the remnants of the terrorist gangs in the area," said a uniformed soldier reading a statement on Syrian television. "This new achievement ... cuts supply lines and tightens the noose around terrorist strongholds remaining in the Damascus countryside," said the soldier.
Syrian officials refer to rebels as "terrorists."
A spokesman of the Islamic Front, a rebel coalition, said fighters fled the hills that overlook Yabroud before Syrian army troops entered. Captain Islam Alloush said other rebels later fled Yabroud overnight, collapsing the ranks of fighters.
"There's no doubt Yabroud had big strategic importance," Alloush said. "This will make it easier for the regime to occupy other nearby villages."
He said the biggest immediate loss would be that rebels now had no way of supplying ranks in rural Damascus where Syrian forces have surrounded a series of opposition-held areas, denying them food, power and clean water.
Gunfire and clashes could be heard on footage broadcast live by the Lebanon-based Al-Mayadeen and Hezbollah station al-Manar. It showed troops walking through empty streets.
A black flag used by Syria's al-Qaida affiliate, the Nusra Front, still flapped from a building near what appeared to be an abandoned rebel army post painted in the colors of a flag used by other rebels: green, white and black.
Kasem Alzein, a Syrian pro-rebel doctor who lives in the nearby Lebanese border town of Arsal, said a hardcore group of fighters decided to remain in Yabroud to fight the death. Three other activists also said rebels aimed to drag Syrian army troops into street-to-street fighting, where they believed they had an advantage.
"They don't want to surrender," Alzein said, even as he glumly acknowledged Yabroud's loss.
"Qusair will repeat itself," Alzein said, referring to another strategic rebel-held town on the Syrian border that fell last summer. As in the Qalamoun offensive, Hezbollah played a key role backing government troops.
Alzein said he hoped rebels could still find a way across the porous border. "They can't close all the mountain pathways. God willing, God will open a path for us," he said.
As Yabroud fell, Syrian helicopters dropped bombs on nearby villages, said the deputy mayor of Arsal, Ahmad Fliti, and the British-based Syrian Observatory for Human Rights.
At least six people were killed, including two children, when military aircraft hit the village of Muarat Yabroud that lies near the fallen town, they said.
Syrian aircraft also fired at least four rockets near Arsal's barren hills targeting fleeing rebels, said the Lebanon's state-run news agency. The NNA said Lebanese soldiers also detained fleeing rebels who tried enter the country with their weapons, and opened fire on a vehicle whose driver did not stop at an army checkpoint.
As Syria's war takes on sectarian tones, it has triggered violence in neighboring Lebanon, which shares a similar patchwork of minorities.
The chaotic mix of rebels fighting Assad forces are overwhelmingly Sunni, while Syria's minorities, including Christians, Shiites and Alawites, have largely sided with the regime or remained neutral. Assad himself is part of the Alawite sect, an offshoot of Shiite Islam.
On Sunday, an extremist Sunni group in Syria, the Islamic State in Iraq and the Levant, claimed responsibility for firing rockets at a Shiite-dominated town near Arsal, local media reported.
One man was killed in the town of Nabi Sheet, while other rockets landed in the nearby town of Labweh on Saturday, Lebanon's state-run news agency said.
In retaliation, Shiite gunmen surrounded Arsal, said resident Mohammed Ezzidine. He said the gunmen were preventing dozens of people from entering the town.
The Syrian war has also exacerbated tensions in the northern Lebanese city of Tripoli dating back to Lebanon's own 1975-1990 civil war. Two impoverished neighborhoods there belonging to rival sects have seen dozens of clashes.
The fighting has left 12 people dead in Tripoli since Thursday, Lebanon's state-run news agency said. NNA said the latest fatality was a soldier.
The clashes pit Sunni gunmen from the neighborhood of Bab Tabbaneh against rivals from nearby Jabal Mohsen, dominated by Alawites.
Hadid reported from Beirut. Barbara Surk contributed reporting from Beirut.