The evacuation of the last remaining civilians and fighters from rebel-held districts of the Syrian city of Aleppo should be completed by Thursday night or Friday, the Red Cross says.
The final phase is expected to take place over multiple stages and involve dozens of buses and hundreds of cars.
Thousands of people are still waiting to be evacuated.
The Red Cross says 34,000 have left the city since the evacuations began eight days ago as part of a ceasefire deal.
The evacuees are being taken to rebel-held territory in the countryside west of Aleppo and the neighbouring province of Idlib, where camps are being set up.
International Committee of the Red Cross (ICRC) spokeswoman Krista Armstrong told Reuters news agency: “The evacuation will continue for the entire day and night and most probably tomorrow (Friday).
“Thousands are still expected to be evacuated.”
A spokesman for the rebel group Ahrar al-Sham, Ahmed Kara Ali, confirmed that “large numbers” of people were still inside the enclave.
The UN estimated a week ago that 50,000 people were there.
Some 400 private vehicles, including pick-up trucks and cars, arrived overnight at the rebel-held town of Khan al-Assal, just to the west of Aleppo, a doctor involved in the operation told AFP. Ms Armstrong said 4,000 people were in the convoy.
The evacuations had earlier been held up for more than 24 hours, forcing thousands of people to spend Tuesday night waiting outside in freezing temperatures with little to eat or drink.
The reasons for the delay were not clear. But state media blamed rebels in Idlib, accusing them of preventing buses from reaching two besieged, pro-government Shia towns that are being evacuated simultaneously as part of the ceasefire deal.
Several buses and ambulances were eventually allowed to enter and leave Foah and Kefraya on Wednesday afternoon, and the ICRC said another four buses would evacuate people from the towns on Thursday.
The Syrian government is waiting for the Aleppo evacuations to be completed before troops move into the rebel enclave and take full control of the city.
Aleppo was once Syria’s largest city, and its commercial and industrial hub, before the uprising against President Bashar al-Assad began in 2011.
For much of the past four years it was divided roughly in two, with the government controlling the western half and rebels the east.
Troops finally broke the deadlock this year with the help of Iranian-backed militias and Russian air strikes, reinstating a siege on the east in early September.
After breaking through the rebels’ defensive lines in mid-November, they quickly advanced and had seized all but 2.6 sq km (1 sq mile) by the time a ceasefire was brokered by Russia and Turkey, which backs the opposition to Mr Assad.