The Syrian army says it has retaken Aleppo entirely and brought "security and safety" back to the city, as the last group of rebel fighters were evacuated.
The last group of rebels and their families holed up in a small enclave in Aleppo were evacuated on Thursday, under a deal that gives the army and its allies full control of the city after years of fighting, state television said.
The end to the evacuation marks Syrian President Bashar al-Assad's assumption of full control over the city after four years of fighting there and hands him his biggest victory of the war so far.
At least 34,000 people, both civilians and fighters, have been evacuated from east Aleppo in a week-long operation, the latest UN figures show. But the United Nations estimates that thousands more remain in eastern Aleppo enclaves.
"The process for evacuation was traumatic, with crowding, and vulnerable people waiting for hours and exposed to sub-zero temperatures," UN spokesman Farhan Haq told reporters in New York.
A senior United Nations official warned on Thursday that thousands of people evacuated from rebel-held areas of Aleppo after the crushing government offensive could suffer the same fate in their new place of refuge outside the city.
"Many of them have gone to Idlib, which could be in theory the next Aleppo," UN Special Envoy Staffan de Mistura said in Geneva.
He said a cessation of hostilities across Syria was vital if another battle like the bloody struggle for Aleppo was to be avoided.
Thousands of refugees from Aleppo were taken to Idlib, arousing fears that the rebel-held city in northwestern Syria could be next. Assad has declared that the war is far from over and that his armed forces would march on other rebel-held areas.
Evacuees from Aleppo had expressed concerns about being taken to Idlib and a senior European diplomat said earlier this month that this would suit Russia, Assad's main military backer, as it would put "all their rotten eggs in one basket".
Assad said that regaining full control of Aleppo was a victory shared by his Russian and Iranian allies.
In comments after meeting a senior Iranian delegation, Assad said his battlefield successes were a "basic step on the road to ending terrorism in the whole of Syria and creating the right circumstances for a solution to end the war".
Russia's air force conducted hundreds of raids that pulverised rebel-held parts of Aleppo while Iranian-backed militias, led by the Lebanese group Hezbollah, poured thousands of fighters to fight rebels into the city.
Defence Minister Sergei Shoigu said Russian air strikes in Syria had killed 35,000 rebel fighters and halted a chain of revolutions in the Middle East.
Shoigu said Moscow's intervention had prevented the collapse of the Syrian state.
Fighters and civilians were evacuated overnight and on Thursday from east Aleppo to opposition-held areas under an agreement between the warring sides, the International Committee of the Red Cross said.
Another rebel official said a heavy snow storm that hit northern Syria and the sheer numbers of civilians still remaining had delayed the mass evacuation.
"The numbers of civilians, their cars alongside and of course the weather all are making the evacuation slow," Munir al-Sayal, head of the political wing of Ahrar al Sham, said, adding he expected the operation to be completed on Thursday.