A Syrian opposition war monitor and two senior army officers said early Sunday that Syrian President Bashar al-Assad has left the country as rebels say they had entered Damascus following a stunning advance across the country, with residents of the capital reporting the sounds of gunfire and explosions.

Rami Abdurrahman of the Syrian Observatory for Human Rights told The Associated Press that Assad took a flight from Damascus early Sunday. Reuters reported the same thing, citing two senior army officers.

An Associated Press journalist in Damascus reported seeing groups of armed residents along the road on the outskirts of the capital and hearing sounds of gunshots. The city's main police headquarters appeared to be abandoned, its door left ajar with no officers outside.

Another AP journalist shot footage of an abandoned army checkpoint where uniforms were discarded on the ground under a poster of Assad's face.

Residents of the capital reported sounds of gunfire and explosions. Footage broadcast on opposition-linked media showed a tank in one of the capital's central squares, while a small group of people gathered in celebration. Calls of "God is great" rang out from mosques.

It was the first time that opposition forces reached the outskirts of Damascus since 2018, when Syrian troops recaptured the area following a years-long siege.

There was no immediate official statement from the Syrian government. The pro-government Sham FM radio reported that the Damascus airport was evacuated and all flights halted.

The insurgents also announced they had entered the notorious Saydnaya military prison north of the capital and "liberated our prisoners" there.

The night before, opposition forces had taken the central city of Homs, Syria's third largest, as government forces abandoned it. Homs is an important intersection between Damascus and Syria's coastal provinces that are the Syrian leader's base of support.