Syria's army on Tuesday urged the last remaining rebels and civilians to leave the bombed-out eastern quarters of Aleppo as it prepares to take full control of the devastated city.
The evacuation of east Aleppo is seen as a pivotal moment in the nearly six-year war that has killed more than 310,000 people and triggered a major humanitarian and refugee crisis.
At least 25,000 people have left rebel districts of east Aleppo since evacuations began last week, according to the International Committee of the Red Cross, which is overseeing the operation.
Thousands more were still waiting to be bused out, spokeswoman Ingy Sedky said.
She said that 750 people had been evacuated in parallel from Fuaa and Kafraya, two Shiite-majority villages in northwest Syria besieged by rebels, as part of the deal.
In east Aleppo on Tuesday, soldiers using megaphones called on the remaining fighters and civilians to exit the opposition districts, a military source told AFP.
"The army is expected to enter (Aleppo) to clean the area after the fighters leave," the source said.
Buses and ambulances have been bringing rebels and civilians on a tense journey from Aleppo's battered east into government-held neighbourhoods, and back into rebel-held territory west of the city.
Thousands of people -- mostly women and children -- squeeze onto buses with whatever belongings they can carry, many in tears and others shivering in the cold, according to AFP correspondents who made the trip.
Evacuees must pass several checkpoints manned by either Syrian army soldiers, Russian officers or Iranian and Iraqi fighters.
"Everyone was so cold," Bashar Babbour, who works with the medical charity UOSSM, told AFP from the staging ground of Khan al-Assal.
He said he saw a shivering old man struggling to get off one of the buses.
"When people are going to the medical assessment teams. Most of them ask for food and water, in addition to blankets, especially if they're arriving at night," Babbour said.
He said many other evacuees were also asking if there was internet access there so they could contact friends or relatives.
The World Health Organization said the evacuees included around 300 needing medical treatment, including dozens of children.
"The huge majority of these patients have trauma injuries," spokesman Tarik Jasarevic said, adding that 93 people in critical condition had been referred to hospitals in Turkey.
Aleppo was once Syria's commercial and industrial hub, but it has been divided since 2012 between government forces in the west and rebel control in the east.
Government forces launched an offensive in mid-November to capture the whole city, and had seized more than 90 percent of the eastern half when the evacuation deal was struck.