BEIRUT, Lebanon (AFP) — Jihadist-led rebels seized Aleppo’s airport and dozens of nearby towns on Saturday after overrunning most of Syria’s second city, a war monitor said.

Damascus ally Moscow responded with its first air strikes on Aleppo since 2016 as the jihadists and their Turkish-backed allies pressed a lightning offensive they launched on Wednesday as a ceasefire took effect in neighboring Lebanon.

In a telephone call with his Emirati counterpart, President Bashar al-Assad vowed to defeat the “terrorists” however big their attacks.

The fighting has killed at least 327 people, most of them combatants but also including 44 civilians, according to the Syrian Observatory for Human Rights.

“Hayat Tahrir al-Sham (HTS) and allied factions... took control of most of the city and government centers and prisons without meeting great resistance,” the Britain-based war monitor said.

They also overran Aleppo airport after government forces withdrew, and took control of “dozens of strategic towns without any resistance,” it added.

The Observatory reported that the army had pulled out of Syria’s fourth largest city Hama, around 140 kilometers south of Aleppo, in the face of the rebel advance.

But a military source cited by state media denied the army had withdrawn, insisting units were still holding their positions in the rebels’ path.

In the heart of Aleppo, an Agence France-Presse (AFP) photographer saw rebel fighters outside the city’s landmark citadel.

The army confirmed that the rebels had entered “large parts” of the city of around two million people, adding that “dozens of men from our armed forces were killed and others wounded.”

HTS is a jihadist alliance led by Al-Qaeda’s former Syria branch which, with its allies, has long controlled a rebel enclave in the Idlib region of the northwest.

Observatory chief Rami Abdel Rahman told AFP that “at this moment, the Syrian regime appears to have been abandoned by its main allies Iran and Russia, with Moscow until now carrying out symbolic strikes.”

Russia carried out air strikes in parts of Aleppo overnight, the Observatory said.

Later on Saturday, “at least 16 civilians were killed and 20 others wounded” in fresh strikes.