The Turkish-backed rebel factions meanwhile capitalised on the government’s retreat by launching a separate offensive on territory north of Aleppo controlled by a Kurdish-led militia alliance supported by the United States, the Syrian Democratic Forces (SDF).

Assad vowed to “crush” the rebels with the help of his allies. Russian warplanes intensified strikes on rebel-held areas and Iran-backed militias sent reinforcements to help the military near Hama – the next city south on the way to Damascus.

But Hama fell to the rebels on Thursday, after several days of fierce battles that eventually prompted the military to withdraw.

The rebels declared their next goal was to take Homs, Syria’s third-largest city, and achieved that on Saturday night after only a day of fighting. At the same time, other rebel factions based reached the suburbs of Damascus.

Early on Sunday, HTS-led rebels announced they had entered Damascus and released detainees at the country’s most notorious military prison, Saydnaya.

Less than two hours later, they declared: “The tyrant Bashar al-Assad has fled.”

Activists and army officers said the president had left Damascus on a plane to an undisclosed location.

Prime Minister, Mohammed al-Jalali, meanwhile announced in a video that he was “ready to co-operate with” any leadership that was “chosen by the Syrian people”.

Abu Mohammed al-Jawlani ordered his forces not to approach official institutions, saying they would remain under the authority of the prime minister until they were “officially” handed over.

The rebels also promised to build a “homeland for all, including all sects and social classes”.

The Syrian Observatory for Human Rights, a UK-based monitoring group, reported that at least 910 people had been killed, including 138 civilians, since the start of the rebel offensive.