Thousands of civilians — including many children — were still trapped inside eastern Aleppo Friday, according to international humanitarian groups, rebels and activists on the ground.
Evacuations from the city's last rebel-held enclave stalled during the operation's second day, with both sides trading the blame for the impasse.
"The evacuation has been aborted and there are negotiations between the different parties to resume it," Elizabeth Hoff, the World Health Organization representative in Syria, told NBC News by phone from inside the city. "There are still thousands of people, including woman and children, inside eastern Aleppo."
The WHO is one of the international organizations involved in the operation. Hoff said it was "not given a reason" why the evacuation had paused.
Hoff's account echoed activists posting on Twitter, as well as rebel groups who said the evacuation was far from over.
"Only the wounded and some civilians left [the city]," Zakaria Malahifji, a Turkey-based official with the Aleppo Fastaqim rebel group, told Reuters. "No fighters came out. Nobody came out. All that came out was three convoys."
However, this was contradicted by Russian officials who claimed the evacuation was complete.
"The operation ... to pull out militants and their family members from eastern Aleppo is finished," the Russian Reconciliation Center in Syria said in a statement. "All women and children in militant-controlled districts have been evacuated."
Rebel sources told Reuters that the evacuation broke down after pro-government militias opened fire on buses carrying civilians.
A Syrian official told the news agency that the rebels had tried to smuggle out captives who they had abducted during the conflict, as well as weapons, something the rebels denied.
The city has been divided between pro-government and rebel forces for much of the war. But in recent months the Syrian regime, backed by Russia, has captured almost all of the rebels' territory.
On Friday, the Russian statement claimed that "gangs of implacable radicals" remained in certain districts and were shelling Syrian forces, who were containing them.
Also causing an impasse was an agreement to evacuate wounded people from the nearby Shiite villages of Foua and Kefraya, a precondition set down by key Syrian ally, Iran.
A media outlet run by the pro-government Hezbollah group said rebels bombed the road into these villages, Reuters reported.