BEIRUT — The Syrian army backed by Lebanese ally Hezbollah has advanced deeper into the besieged Syrian city of Zabadani two weeks into a campaign to capture it from insurgents, both rebels and the army said.

The control of the city, about 30 miles northwest of the capital Damascus, is seen as crucial to consolidate government-held areas linking Lebanon and Syria. Zabadani is a former popular resort on the main Beirut-Damascus highway.

Hezbollah militiamen and the army, aided by reinforcements, advanced closer to Zabadani’s center under cover of heavy artillery fire and intense aerial bombardments of insurgent hideouts, according to both rebels and the army.

Footage released by the Syrian army showed troops in the heart of the southeastern district of Sultani, the focus of street fighting. Rebels said some 500 families were still inside Zabadani and had taken shelter, but the city was mostly deserted.

A victory over the rebels would secure a corridor for Hezbollah to transport fighters and arms. The group’s military role inside Syria has been growing steadily since the start of the conflict in 2011.

Hezbollah’s leader, Hassan Nasrallah, stressed the group’s commitment to the fight in Syria. 

“The road to Jerusalem goes through Qalamoun, Zabadani, Homs, Aleppo, Deraa, Hassakeh and Swaida, because if Syria was lost, Palestine would be lost too,” he said, arguing that the Syrian regime is vital in the fight against Israel.