DAMASCUS — Thousands of Syrian insurgents moved into Aleppo on Saturday, taking control of significant landmarks such as the historic citadel and the city center, a day after entering Syria's largest city with little resistance from government forces.

Residents and fighters reported the insurgents deploying in armored vehicles and pickups across the city.

The Syrian military issued a statement acknowledging the insurgents’ advance and announced a redeployment to absorb the attack and prepare for a counteroffensive.

The military stated the insurgents had not yet established bases or checkpoints but emphasized its intent to restore security.

The insurgents' surprise takeover is a major blow to Syrian President Bashar Assad, who had regained full control of Aleppo in 2016 after a brutal campaign.

The city, a former opposition stronghold, had been under government control since then, making the insurgents’ push a significant setback.

The offensive, launched Wednesday in the Aleppo and Idlib countryside, saw insurgents capture dozens of villages before reaching Aleppo.

Fighters were seen removing posters of Assad and raising opposition flags over the Aleppo Citadel, a symbol of the city’s heritage and history.

Late Friday, airstrikes targeted insurgent reinforcements on Aleppo’s outskirts, killing 20 fighters, according to the Syrian Observatory for Human Rights.

Residents reported clashes and sporadic gunfire in parts of the city. Some civilians fled the fighting, with schools and government offices closing on Saturday.

The U.N. Office for the Coordination of Humanitarian Affairs (OCHA) reported that Aleppo’s airport was shut down, flights were suspended, and hospitals were overwhelmed with patients, while many private medical facilities closed due to the instability.

Opposition fighters were seen celebrating in Aleppo’s streets, firing into the air but deploying security forces to prevent looting. Videos shared on social media showed insurgents visiting residents to reassure them of their safety.

The Syrian Kurdish-led administration in eastern Syria reported that nearly 3,000 people, most of them students, had fled Aleppo for Kurdish-controlled areas. The city has a sizable Kurdish population, adding another layer of complexity to the ongoing conflict.

Russia’s Defense Ministry claimed its warplanes killed 200 militants during strikes on Friday but provided no further details. — Agencies