Syrian Army Readying Assault on Last Rebel-Held Areas in Qalamoun

Syrian regime forces were on Monday readying an assault on the last rebel-held areas in the Qalamoun mountains, strategically located on the Lebanese border, after overrunning key opposition bastion Yabrud.

The capture of Yabrud on Sunday by Syrian troops and Hizbullah fighters came shortly after the conflict entered its fourth year and marked a significant setback for the rebels as it severs their supply lines from across the border.

A security source in Damascus said the army would soon launch operations "in all areas where terrorists are to be found," using the regime's term for rebels battling to topple the Assad regime.

"The aim of the army operation is to entirely secure the border and to close all corridors to Lebanon."

The fighting along the border has sparked a fresh flight of civilians into Lebanon, which is already hosting nearly a million refugees, according to the U.N. High Commissioner for Refugees.

"So far 150 families have crossed the border since Yabrud fell," said the UNHCR's Lisa Abu Khaled.

"NGOs there were on standby so they have handed out food, blankets, etc, and the U.N. plans to register the arrivals this week."

Speaking to Agence France Presse via the Internet from the Qalamoun mountains, activist Jawad al-Sayed said all civilians were "evacuated" from Yabrud before the town fell, either to areas nearby or to neighboring Lebanon.

The road, he said, was dangerous, echoing reports from a day earlier that at least six people, including two children, were killed in air strikes as they fled for Lebanon.

"The situation of the civilians is very sad... So we have two options, either to go to Lebanon... or to stay here and resist," said Sayed.

Nineteen Syrian men and two Lebanese were arrested Monday after crossing the border illegally, said the Lebanese Army, adding that the men had in their possession an assault rifle, two pistols, cash and 30 mobile phones.

The fall of Yabrud came after five months of Syrian army operations in the Qalamoun region, and more than 30 days of heavy aerial bombardment of the town.

An AFP reporter entered Yabrud, north of Damascus, on Sunday after the army declared it had seized full control of the town.

Exhausted Syrian soldiers sat in the streets after seizing the town in fierce clashes with the support of battle-hardened Hizbullah fighters and pro-regime militiamen.

"It was a very difficult battle, possibly the most difficult we have faced," a soldier who identified himself as Abu Mohammed told AFP in Yabrud's central square between puffs from a water-pipe.

A source close to Hizbullah in Lebanon's Bekaa Valley told AFP that the victory came after a Hizbullah commando raid on Yabrud during which 13 rebel leaders were killed, leaving their forces in disarray.

Among those killed, said the source, was Abu Azzam al-Kuwaiti, a key commander in al-Nusra Front, al-Qaeda's official Syrian affiliate.

Yabrud was once home to some 30,000 people, including a Christian minority, and had been a rebel bastion since early in the Syrian uprising, which began in March 2011 in the form of peaceful protests.

The town is a strategic prize because of its proximity to the highway and the Lebanese border, across which the mostly Sunni rebels have smuggled fighters and weapons.

Hizbullah's involvement in Syria has prompted bomb attacks by extremist groups against areas in Lebanon sympathetic to the group, killing mostly civilians.

Syria's three-year conflict has claimed an estimated 146,000 lives and displaced millions of people.