SYRIA  -  Syrian armed rebels Friday entered Aleppo just three days into their surprise offensive, marking the first time they have set foot in the country’s second largest city since government forces recaptured the city in 2016.

Rebel forces launched a surprise attack this week, sweeping through several villages outside the city and reigniting conflict that had been largely static for years.

In a video geolocated by CNN, a rebel fighter films as he drives through the deserted streets on the western side of the city. He is heard praising God as the vehicle approaches the Zine El Abidine Mosque in western Aleppo.

The official Syrian military said it was confronting a “major attack” and claimed it is “reinforcing all locations along the various battlefronts,” but multiple residents of the city say regime forces have pulled back from several neighborhoods in the western part of Aleppo.

The offensive, which began Wednesday, is the first major flare-up in years between the Syrian opposition and the regime of President Bashar al-Assad, who has ruled the war-torn country since 2000.

“Our forces have begun entering the city of Aleppo,” said the newly formed rebel coalition, the Military Operations Command.

The rebel group announced earlier that it had seized control of the Syrian government’s Military Scientific Research Center on the outskirts of Aleppo city after “intense clashes with the regime forces and Iranian militias.”

In an attack earlier Friday, an artillery shell struck Aleppo University’s student housing, killing four people, according to Syria’s state news agency, SANA, which blamed opposition factions for the attack. The spokesperson for the rebel groups Hassan Abdulghani refuted the accusations by the Syrian government media as “baseless lies.”

An Aleppo University employee, speaking anonymously for security reasons, confirmed that an artillery shell hit the second floor of a dormitory with students inside at the time. A video circulating on social media, geolocated by CNN, shows young men running out of a dormitory in Aleppo University campus and carrying an injured individual.

On Thursday, at least 15 civilians, including six children and two women, were killed, and 36 others were injured in airstrikes and shelling on rebel-held areas in Aleppo and Idlib countryside, according to the White Helmets, a volunteer rescue group. Iranian state media said that an Islamic Revolutionary Guards Corps (IRGC) Brigadier General Kioumars Pourhashemi was also killed in the city.