The final phase of evacuations from former rebel strongholds in eastern Aleppo are under way.
Some families are huddling around fires amid sleet and snow as they prepare for their departure from the war-torn city.
The International Committee of the Red Cross said all patients and those needing medical care had been moved out of the last hospital in the east on Wednesday evening.
Once the evacuations are completed, the government can assume full control of Aleppo, more than four years after opposition fighters seized large areas of what was once Syria's largest city.
Syrian opposition fighters agreed last week to surrender their last foothold in the city, marking the most significant victory for President Bashar Assad since an uprising against his family's four-decade rule swept the country in 2011.
The deal followed a punishing offensive by government troops and military allies Russia and Iran that drove out tens of thousands of civilians from rebel-held areas of the city.
Thousands of fighters and civilians - with estimates ranging between 18,000 and 25,000 - have been bussed out of eastern Aleppo since the evacuations began last week.
The opposition's British-based Syrian Observatory for Human Rights said on Wednesday that some 3,000 fighters and civilians were still awaiting evacuation from the city's last opposition-held neighbourhoods, where some 60 buses were to transport them out.
A convoy of buses and cars later drove out of the city under heavy snow.
By Wednesday evening, 25 buses from eastern Aleppo had reached the government-held western outskirts of the city, said opposition activist Ahmad Primo.
The bus movements came after evacuations had been suspended for 24 hours. Syrian state TV said they had resumed after rebels handed over prisoners taken in previous rounds of fighting.
As part of a wider deal, rebels are supposed to allow evacuations of the sick and wounded from two rebel-besieged villages, Foua and Kfarya. The ICRC said about 750 people have already been bussed out of the villages, leaving hundreds more to be evacuated.
Meanwhile, freezing temperatures worsened already dire conditions in eastern Aleppo, where months of heaving bombardments have caused large-scale devastation.
Activists circulated photos on social media of families huddled around fires amid the sleet and snow.
The international group Save The Children said the cold is further hampering aid efforts on the ground, amid chronic shortages of food, medicine and blankets.
A seven-year-old Syrian girl who was evacuated on Monday and whose mother ran a Twitter account in her name met on Wednesday with Turkish President Recep Tayyip Erdogan in the Turkish capital, Ankara.
Bana Alabed's mother, Fatemah, set up and began operating the account in September, tweeting on her daughter's behalf. The account has garnered some 354,000 followers.
The child's social media account has included tweets to people such as Michelle Obama and Turkish foreign minister Mevlut Cavusoglu, asking them for help.
Elsewhere in northern Syria, fighting between the Islamic State group on one side, and Turkish and Syrian opposition forces on the other, killed four Turkish soldiers, according to Turkey's state Anadolu news agency.
The report cited unnamed military sources as saying that 11 Turkish soldiers were also wounded in the fighting for the IS-held town of al-Bab, including one who was in critical condition. The agency reported intense clashes near a hospital in the town, saying the militants were using it as a shelter and to store arms and ammunition.
Turkey sent ground troops into northern Syria in August to support Syrian opposition forces in clearing a border area of Islamic State group militants and to curb Kurdish territorial expansion.
At the United Nations, the UN Security Council approved the delivery of humanitarian aid across borders and conflict lines in Syria for another year, in a resolution aimed at reaching thousands in need in rebel-held areas without government approval.
The resolution, adopted unanimously, expresses grave distress at "the continued deterioration of the devastating humanitarian situation in Syria", where more than 13.5 million people require urgent assistance.
It cited the alarming situation in besieged areas where hundreds of thousands of civilians are trapped.