Diplomats are seeking to salvage the evacuation of eastern Aleppo after it stalled amid recriminations by opposing sides in the Syrian conflict.
The Aleppo evacuation was suspended after a report of shooting at a crossing point into the enclave. The Syrian government subsequently pulled out its buses that had, since Thursday, been ferrying out people from the ancient city that has suffered under intense bombardment, fierce battles and a prolonged siege.
The halt also appeared to be linked to a separate deal to remove thousands of people from the government-held Shi'ite villages of Foua and Kfarya that are under siege by the rebels.
The Syrian government says those evacuations and the one in eastern Aleppo must be done simultaneously, but the militant groups say there's no connection.
The foreign minister of Turkey, a main backer of the rebels, said he was talking to his counterpart in Iran, an ally of the Syrian government, to try to resume the evacuation.
A closed emergency meeting of the UN Security Council was held on the crisis in Aleppo, discussing a French proposal to have independent monitors oversee the relocation of civilians and fighters. The council meeting ended with diplomats saying they would convene again on the weekend.
The ceasefire and evacuation marked the end of the rebels' most important stronghold in the 5-year-old conflict.
The suspension demonstrated the fragility of the ceasefire deal, in which civilians and fighters in the few remaining blocks of the rebel enclave were to be taken to opposition-held territory nearby.
In announcing the suspension, Syrian state TV said rebels were trying to smuggle out captives who had been seized in the enclave after ferocious battles with troops supporting the government of President Bashar al-Assad.
Several opposition activists said Syrian troops shot and killed four people in one bus, but the incident could not be independently confirmed.
The Lebanon-based pan-Arab Al-Mayadeen TV broadcast images of the government buses apparently returning evacuees to eastern Aleppo after the road was closed.
Al-Manar TV, the media arm of Hezbollah that supports Assad, said Syrian government supporters had closed the road used by evacuees from Aleppo, demanding the wounded from Foua and Kfarya be allowed to leave.
Syrian state media said rebels shelled a road that was supposed to be used by people leaving the villages. But the opposition's UK-based Syrian Observatory for Human Rights said Hezbollah fighters backed by Iran had cut the road to protest a lack of progress in the evacuations.
Buses that arrived at a collection point in the Hama countryside to pick up evacuees from the villages waited for hours to no avail.
Later, two rebel spokesmen privy to the talks said the insurgents besieging the villages, including the Fatah al-Sham Front, had agreed to let several hundred wounded leave the villages.
Turkey's state-run Anadolu Agency said Prime Minister Binali Yildirim had called Iranian Presidential Deputy Ishak Cihangiri and told him he was ready to co-operate with Tehran on the evacuation issue.
Reports differed on how many people remain in the Aleppo enclave, ranging from 15,000 to 40,000 civilians, along with an estimated 6000 insurgents.
There are still "high numbers of women and infants, children under 5, that need to get out," said Elizabeth Hoff, Syrian representative for the World Health Organisation, speaking by phone from western Aleppo.
Before the operation was suspended onFriday, four convoys of ambulances and buses left Aleppo, Syrian state TV said, noting that some evacuees used their own vehicles.
In Japan, Russian President Vladimir Putin announced a new peace initiative, saying he and Turkish President Recep Tayyip Erdogan were working to set up talks between Damascus and the opposition. Putin said they would take place in Astana, the capital of Kazakhstan.
Bassma Kodmani of the High Negotiations Committee, Syria's main opposition group, said her group supports the call for resumed peace talks but it wants them to take place under UN auspices and that it doesn't believe Astana was "the appropriate place".