A deal to allow the safe evacuation of families from eastern Aleppo has been suspended.
Before it stalled, around 8,000 people left eastern Aleppo in the buses, with an estimated 50,000 remaining.
The evacuations were taking place along humanitarian corridors to the west of the city.
The United Nations believes at least 2,700 children were among the evacuees, some without their parents.
Those who managed to escape in the initial evacuation fled with absolutely nothing, with one evacuee, Shihab* telling World Vision his family queued for five hours to get on a bus, but everyone had to leave their luggage behind as the vehicles were so crowded.
"The buses started picking people around 12:00 a.m. It was chaos; the number of people were way too much for the buses. I didn’t manage to get into one before 5:30 am,” he said.
"I can’t describe how it was. There are no words to describe how we felt. There were a lot of families and children. No one was organising anything. People were just keen to get out. A lot of people got pushed around, sometimes beaten.”
He said many people burned their possessions as they waited in freezing conditions to try and keep warm.
People fleeing Aleppo are starting to arrive at reception centres managed by NGOs, where World Vision has sent mattresses and blankets to be distributed to new arrivals.
World Vision is working in Tel Abiad, A’zaz, Jarabulus, and Manbij Districts, providing people with winter supplies, clean water and sanitation services, food, and emergency supplies.
World Vision is also supporting the district’s women and children’s’ hospital with equipment and supplies.