Abandoned Syrian army armoured vehicles sit on a road as rebel forces advance on the outskirts of Hama on December 3, 2024. Photo: AP

Hama was a bastion of opposition to the government of President Bashar al-Assad early in the country's civil war, which erupted in 2011.

It was also the scene of a massacre in the 1980s under the rule of Assad's father, whose scars have yet to heal even four decades on.

The Syrian Observatory for Human Rights said that "after midnight, regime forces launched a counterattack" with air support on Hayat Tahrir al-Sham (HTS) rebels and allied factions near Hama.

Government forces pushed HTS away from the provincial capital by about 10 kilometres (six miles), the Observatory said, reporting "fierce battles" as rebels "failed to control" an area near the city.

In a sudden flare-up in Syria's 13-year civil conflict, Islamist-led rebels and allied fighters last week launched a lightning offensive from their bastion in the northwest, marching on neighbouring Aleppo province and taking the country's second city from government control.

Syrian state news agency SANA said Wednesday that the army was continuing operations against "terrorist organisations" in northern Hama province.

It said "army units are engaged in violent clashes with various types of weapons" on axes northeast and northwest of the city.

The Observatory said the government forces in Hama province had received military reinforcements.

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

The Britain-based Observatory had said Tuesday that Syrian rebel forces arrived at the gates of the key city of Hama, as the fighting sparked a large wave of displacement.

Syrian state television broadcast footage through the night showing squares in Hama city empty except for soldiers and police.

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

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