Thousands of rebels also scattered across Aleppo in makeshift armored vehicles and pickup trucks, a day after entering the city.
According to residents and fighters, the rebels faced little resistance from government troops during the shock offensive.
Witnesses said two airstrikes on the outskirts of the city late Friday targeted rebel reinforcements and hit near residential areas. A war observer said 20 fighters were killed.
The Syrian Armed Forces said in a statement on Saturday that they had redeployed and were preparing for a counterattack to absorb a major attack on Aleppo and save lives. The statement acknowledged that the rebels had entered large parts of the city, but said they had not established bases or checkpoints.
The rebels were filmed in front of the police headquarters, in the city center and in front of the Aleppo Citadel. They tore up posters of Syrian President Bashar Assad, trampled on some, and burned others.
The surprise takeover is a major step for Assad, who managed to regain full control of the city in 2016, after driving rebels and thousands of civilians from its eastern neighborhoods following a grueling military campaign in which his forces were backed by Russia, Iran and its allies.
Aleppo has not been attacked by opposition forces since then. The 2016 battle for Aleppo was a turning point in the war between Syrian government forces and rebel fighters after protests against Assad’s rule in 2011 turned into all-out war.
At the time, Russian warplanes repeatedly carried out deadly airstrikes, helping Assad regain control.
Friday’s attack on Aleppo followed weeks of low-level violence, including government attacks on opposition-held areas. Turkey, which backs opposition groups, has failed in its efforts to prevent government attacks, which have been seen as a violation of a 2019 agreement sponsored by Russia, Turkey and Iran to freeze the conflict line.
The offensive came as Iran-linked groups, primarily Lebanon’s Hezbollah, which has backed Syrian government forces since 2015, were preoccupied with their own battles at home. A ceasefire in Hezbollah’s two-month war with Israel took effect on Wednesday, the day Syrian opposition factions announced an offensive. Israel has also escalated its attacks on Hezbollah and Iran-linked targets in Syria over the past 70 days.
A witness in Aleppo said that government troops remained at the city’s airport and at the military academy, but that most of the forces had already left the city from the south. Syrian Kurdish forces remained in two settlements.
The redeployment is “a temporary measure and (the central military command and the armed forces) will work to guarantee the safety and peace of all our people in Aleppo,” the military said in a statement.
Speaking from the heart of the city in Saadallah Aljabri Square, opposition fighter Mohammad Al Abdo said it was his first time in Aleppo after 13 years, when his older brother was killed at the start of the war.
“God willing, the rest of Aleppo province will be liberated” from government forces, he said.
There was light traffic in the city center on Saturday. Opposition fighters fired into the air in celebration, but there were no signs of clashes or the presence of government troops.
Abdulkafi Alhamdo, a teacher who fled Aleppo in 2016 and returned on Friday night after hearing that rebels were inside, described “mixed feelings of pain, sadness and old memories”.
“While I was entering Aleppo, I kept telling myself that this is impossible! How did this happen?” He said he walked around the city at night, visited the citadel, where the rebels raised their flags, the main square and the university in Aleppo, as well as the last place he visited before he was forced into the countryside.
“I walked the (empty) streets of Aleppo, shouting: ‘People, people of Aleppo. We are your sons,’ Alhamdo told The Associated Press in a series of messages.
Rebels launched a shock offensive in the countryside of Aleppo and Idlib on Wednesday and seized control of dozens of villages and towns before entering Aleppo on Friday.
Schools and government offices were closed on Saturday as most people stayed indoors, according to Sham FM radio, a pro-government station. Witnesses said the rebels had deployed security forces around the city to prevent any violence or looting.
The UN Office for the Coordination of Humanitarian Affairs announced that the city’s airport was closed and all flights were suspended. On Friday, two key public hospitals in Aleppo were reportedly full of patients, while many private facilities were closed, OCHA said.
In social media posts, rebels were shown outside the Aleppo Citadel, a medieval palace in the old city center and one of the largest in the world. On cellphone videos, they recorded themselves talking to residents they were visiting at home, trying to reassure them that they would cause no harm.
The administration in the country’s east led by Syrian Kurds said nearly 3,000 people, mostly students, had arrived in their areas after fleeing fighting in Aleppo, which has a significant Kurdish population.
State media reports that numerous “terrorists”, including sleeper cells, have infiltrated parts of the city. Government troops chased them and arrested a number who were taking pictures near city landmarks, according to state media.
On a morning broadcast on state television on Saturday, commentators said Russia’s military reinforcements and aid would repel “terrorist groups”, accusing Turkey of supporting a rebel attack on Aleppo and Idlib provinces.
Russian state news agency Tass quoted Oleg Ignasyuk, a Russian defense ministry official coordinating in Syria, as saying that Russian warplanes targeted and killed 200 militants who launched an offensive in the northwest on Friday. It gave no further details.