Aleppo (Syria) (AFP) - A ceasefire in the Syrian army's Russian-backed assault on rebel-held Aleppo appeared to expire Saturday with the UN saying it had been unable to evacuate anyone from the ravaged city.
Moscow had extended the unilateral "humanitarian pause" into a third day until 1600 GMT on Saturday, but announced no further renewal of the truce despite a UN request for longer to evacuate wounded civilians.
Neither residents nor rebels in the opposition-held part of the city heeded calls from Syria's army and Moscow to leave, after weeks of devastating bombardment and a three-month government siege.
The pause began on Thursday, and came after Moscow announced a temporary halt to the Syrian army's campaign to recapture the divided city.
The army opened eight corridors for evacuations, but just a handful of people crossed through a single passage, with the others remaining deserted.
"Members of popular civil committees from regime districts entered the eastern neighbourhoods to try to evacuate the injured but failed," Rami Abdel Rahman, head of the Syrian Observatory for Human Rights, said on Saturday.
Syrian state media and Russian authorities have accused rebels in the east of preventing civilians from leaving and using them as "human shields".
- Guarantees not received -
More than 2,000 civilians have been wounded since the army launched its offensive to drive the rebels out of the eastern districts they have held since 2012. Nearly 500 people have been killed.
The United Nations had hoped to use the ceasefire to evacuate seriously wounded people, and possibly deliver aid.
But a UN official said on Saturday that the requisite security guarantees had not been received.
"You have various parties to the conflict and those with influence and they all have to be on the same page on this and they are not," said David Swanson, a spokesman for the UN humanitarian office.
The UN had drawn up a four-day plan that would start with two days of medical evacuations to west Aleppo, rebel-held Idlib province, and Turkey, and continue with more evacuations as well as aid deliveries.
No aid has entered Aleppo since July 7 and food rations will run out by the end of the month, UN chief Ban Ki-moon warned on Thursday.
The UN had asked Moscow to consider extending the pause until Monday evening, but there was no word of any extension as the 1600 GMT deadline passed.
- Fears of renewed fighting -
Moscow accuses rebels of preventing civilians from leaving.
"The terrorists are using the ceasefire in their interests," said senior Russian military official Sergei Rudskoi.
"We are seeing them massing around Aleppo and preparing for another breakthrough into the city's western neighbourhoods."
Russia is a key ally of Syria's government and began a military intervention in support of President Bashar al-Assad last September.
Kremlin spokesman Dmitry Peskov said in an interview set to air Saturday evening that the intervention was meant to "liberate" Syria and keep Assad in power.
"Either Assad is in Damascus, or Al-Nusra is," he said, referring to former Al-Qaeda affiliate the Fateh al-Sham Front. "There is no third option here."
The Observatory said both rebels and regime forces appeared to be reinforcing their positions in preparation for renewed fighting if the truce ended.
"The regime and the rebels are both bolstering their forces, which raises fears of a massive military operation if the ceasefire fails," Abdel Rahman told AFP.
Elsewhere in Aleppo, Turkish forces and allied Syrian rebels were carrying out heavy shelling of the Kurdish-Arab Syrian Democratic Forces in several villages.
Turkey considers the Kurdish militia that leads the SDF to be a "terrorist" organisation, and began an operation in Syria in August targeting the militia and the Islamic State group.
On Friday, the UN human rights council called in a resolution for "a comprehensive, independent special inquiry into the events in Aleppo".
It also demanded that warring parties provide unrestricted humanitarian access to desperate civilians and "end immediately all bombardments and military flights over Aleppo city".
Also Friday, UN experts said the Syrian army was responsible for a March 2015 chemical weapons attack on the village of Qmenas.
But they said they were unable to determine who was responsible for two other chemical weapons attacks, one in the same month and the other in April 2014.
French Foreign Minister Jean-Marc Ayrault on Saturday urged the UN Security Council to issue a "clear condemnation" of chemical weapons use in Syria in a resolution "that places the perpetrators under sanctions".