Syria crisis: More than 1,000 people leave rebel-held Aleppo pocket in new evacuation

More than 1,000 people were evacuated from the last rebel-held pocket of Syria's Aleppo early on Monday after hours of delay, a medical official said.

"About 20 buses carrying people from Aleppo have arrived" at the staging ground west of the city, said Dr Ahmad Dbis, who heads a team of doctors and volunteers coordinating evacuations. "There are about 1,200 to 1,300 people here," he said.

More than 30 buses packed with people had waited overnight in freezing temperatures to leave Aleppo under a complex evacuation deal.

Just 350 people were able to leave after Russia and Turkey urged the Syrian regime to allow five buses to pass its final control point, the Syrian Observatory for Human Rights said.

The departure of the remaining buses had reportedly been delayed until hundreds of people could be evacuated from two villages in northwestern Syria under siege by the rebels.

The Britain-based Observatory said an estimated 500 people were bussed out of Fuaa and Kafraya.

"Ten buses carrying about 500 people have left Fuaa and Kafraya and are on their way to government-controlled territory in Aleppo," said Observatory head Rami Abdel Rahman.

The evacuation deal for Aleppo was brokered by regime ally Russia and rebel backer Turkey, and has been overseen by the International Committee for the Red Cross.

UN envoy Staffan de Mistura estimated that as of Thursday around 40,000 civilians and perhaps as many as 5,000 opposition fighters remained in Aleppo's rebel enclave.