Beirut (Lebanon) (AFP) - Islamist-led rebels advanced Tuesday on Syria’s fourth-largest city Hama, buoyed by their lightning capture of swathes of the north in an offensive that ended four years of relative calm.

The sudden flare-up in the more than decade-old civil war in Syria drew appeals for de-escalation from across the international community.

Islamist group Hayat Tahrir al-Sham (HTS) and its allies met much tougher resistance in the countryside north of Hama than they did in the Aleppo region on Friday and Saturday, the Britain-based Syrian Observatory for Human Rights said.

The Observatory reported the heaviest fighting with government forces so far as the offensive entered its seventh day.

“Clashes have erupted in the northern Hama countryside, where rebel factions managed to seize several cities and towns in the last few hours,” the Observatory said.

“Syrian and Russian air forces carried out dozens of strikes on the area.”

A statement from Syria’s army command said its forces were striking “terrorist organisations” in north Hama and Idlib provinces, with Russian air support.

It said reinforcements were continuing to arrive and reported “fierce battles”, particularly in the north of Hama province.

Russia is a key ally of President Bashar al-Assad. Its 2015 intervention in the Syrian civil war turned the tide in his government’s favour but since 2022 the Ukraine war has tied down much of its military resources.

- ‘Threat’ to popular base -

Hama was a bastion of opposition to the Assad government early in the civil war.

For many of the city’s residents, the scars of a 1982 massacre by the army aimed at crushing the banned Muslim Brotherhood, have yet to heal.

But its capture by the rebels would “pose a threat to the regime’s popular base”, Observatory director Rami Abdel Rahman said.

The countryside west of the city is home to many Alawites, followers of the same offshoot of Shiite Islam as the president and his security chiefs.

An AFP journalist in the northern Hama countryside saw dozens of Syrian army tanks and military vehicles abandoned by the side of the road leading to Hama.

“We want to advance on Hama after combing” towns that have been captured, a rebel fighter who identified himself as Abu al-Huda al-Sourani told AFP.

The United Nations says nearly 50,000 people have been displaced by the fighting since it began last Wednesday.

At least 602 people have been killed, mostly combatants but also including 104 civilians, according to the Observatory.

- UN alarm -

The exodus of civilians just as winter takes hold has triggered international concern.

UN chief Antonio Guterres said he was “alarmed” by the violence and called for an immediate halt.

The European Union and the United States called on all sides to de-escalate.

Assad is no longer the pariah in the Arab world that he was at the height of the civil war.

At a summit in Cairo last year, Arab leaders agreed to reinstate Syria’s membership of the Arab League, marking the start of a slow rehabilitation.

Turkish ally Qatar has been the main exception, refusing to normalise relations with Assad’s government.

Its foreign ministry spokesperson Majed Al-Ansari denied any military role in the rebel offensive but said a negotiated settlement between the warring parties was the only way to end the conflict.

- Civilian exodus -

One anxious resident of Syria’s second city Aleppo, who declined to be identified, spoke of panic as the rebels overran it on Friday and Saturday.

“There were terrible traffic jams,” he said.

HTS has its origins in Al-Qaeda’s former Syria branch and has faced accusations of human rights abuses including torture.

A convoy of Kurds joined the exodus on Monday as Turkish-backed fighters seized areas east of Aleppo from the Kurdish-led Syrian Democratic Forces, who control much of the northeast, an AFP photographer witnessed.

But others remained trapped inside the rebel-controlled city.

Nazih Yristian, 60, who lives in Aleppo’s Armenian neighbourhood, said he and his wife had tried to flee but the main road out had been cut. Since then, the couple have cloistered themselves at home, he said.

“No one attacked us so far, but we want to leave until things calm down. We have been displaced a lot and we will be displaced again.”

The Norwegian Refugee Council warned that the rebel offensive “threatens to drag the country back into the darkest days of this near 14-year conflict”.

“In Aleppo, NRC teams report food shortages as bakeries and shops shut down. Damage to water networks has also reduced domestic water supplies,” its Middle East and North Africa director Angelita Caredda said.

Russian President Vladimir Putin and his Iranian counterpart Masoud Pezeshkian pledged “unconditional support” for their ally, according to the Kremlin.

Putin later urged a “speedy” end to the offensive during a phone call with his Turkish counterpart Recep Tayyip Erdogan.

Turkish forces and their proxies have controlled swathes of territory in northern Syria since 2016.

Iran’s Foreign Minister Abbas Araghchi meanwhile said: “If the Syrian government asks us to send forces to Syria, we will study their request.”

Neighbouring Iraq too has expressed support, and on Tuesday a pro-Iran group within the security forces called on the government to go further and send combat troops.

A spokesman for Kataeb Hezbollah, part of the Iran-backed “axis of resistance”, said the group had not yet decided to deploy its own fighters but urged Baghdad to act.

“We believe the Iraqi government should take the initiative to send regular military forces in coordination with the Syrian government,” the spokesman said.

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