After Aleppo cease-fire, Syrian rebel and civilian pullout delayed

The pullout of Syrian rebels and civilians from their last holdout in the city of Aleppo was delayed on Wednesday, though it wasn't immediately clear what had caused the delay.

The withdrawal was expected to start early in the early morning hours after the remaining rebel factions the previous day reached a cease-fire deal to evacuate from eastern Aleppo in what is effectively a surrender of the city's few remaining opposition-run neighborhoods to government control — and a defining moment in Syria's civil war.

An opposition official told The Associated Press on Wednesday that there were 800 sick and wounded people requiring immediate medical evacuation from eastern Aleppo.

The last-minute deal was mediated by Ankara and Moscow as the rebel enclave rapidly dissolved and ceded more and more territory in the face of the brutal advance by Syrian forces, backed by Russia and assisted by Shiite militias from Lebanon, Iraq and Afghanistan.

Late on Tuesday, the U.N. envoy for Syria, Staffan de Mistura, called for immediate access to the former rebel enclave to confirm the end of military operations and to oversee the safe departure of tens of thousands of civilians and opposition fighters from the last sliver of eastern Aleppo into which they had been squeezed by the advancing government forces.

De Mistura was at the Security Council where an emergency meeting for Aleppo was held.

The pan-Arab al-Mayadeen TV broadcast on Wednesday footage of Syrian government buses idling at an agreed-on evacuation point. It was not immediately clear what has caused the delay.

The TV said it expected at least another couple of hours of delay. It said the buses are prepared to move 5,000 fighters and their families to Atareb, an opposition-held town in the northwestern Aleppo countryside.

Brita Haj Hassan, a Syrian opposition official living in exile, told The Associated Press from Luxemburg that the U.N. and other intermediaries had informed the opposition that the evacuation had been delayed until Thursday.

However, here was no comment from the government, the United Nations or aid groups on the ground. Haj Hassan, who is on the opposition's local council for Aleppo, said he blamed Russia and Iran for the delay.

The dramatic developments surrounding Aleppo — which would restore the remainder of what was once Syria's largest city to President Bashar Assad's forces after months of heavy fighting and a crippling siege — followed reports of mass killings by government forces closing in on the final few blocks still held by the rebels.

U.N. Secretary-General Ban Ki-moon told the emergency meeting late Tuesday that he had received "credible reports" of civilians killed by pro-government forces as they swept into the last rebel areas in Aleppo.

"To the Assad regime, Russia and Iran —three member states behind the conquest of and carnage in Aleppo — you bear responsibility for these atrocities," said U.S. Ambassador Samantha Power.

Bashar al-Ja'afari, Syria's U.N. ambassador, denied any mass killings or revenge attacks, but added it was Syria's "constitutional right" to go after "terrorists," a reference to all opposition fighters.

"Aleppo has been liberated from terrorists and those who toyed with terrorism," he said. "Aleppo has returned to the nation."