Both sides had accused the other of breaking the ceasefire
A ceasefire deal to allow Syrian rebels and thousands of civilians to be evacuated from the last opposition-held area of eastern Aleppo is apparently back on track.
The fragile truce, brokered by Russia and Turkey, had collapsed after less than a day when airstrikes, gunfire and shelling broke out.
But it is due to begin again "within hours" after a reciprocal arrangement to evacuate two villages Foua and Kefraya that are besieged by rebels in Idlib province.
Around 15,000 people will be able to leave the two areas, which was a condition introduced by the Syrian government for the truce deal to resume.
Earlier, Syrian president Bashar al Assad hit out at the ceasefire.
He said it was designed to "keep the terrorists and save them" and stop his government's advance on the last tiny pockets of resistance.
He said western countries had pressured Russia for the ceasefire when rebels appeared to be on the verge of losing all their territory in the war-torn city.
It meant the mass evacuation of rebels and thousands of civilians in the last rebel-controlled area - a square-mile pocket in the east - was delayed.
The withdrawal had been due to begin at 5.00am (3.00am GMT) but was on hold, as shelling took place and civilians were trapped.
Syrian government buses that had been waiting at an agreed point returned to their depots.
Turkey's President Erdogan and Russia's President Putin later agreed in a telephone call to make a joint effort to start the evacuation as soon as possible, according to Turkish presidential sources.
Meanwhile, Iranian President Hassan Rouhani has congratulated Preident Assad on a victory in "liberated Aleppo", saying it was an important step towards "wiping out terrorism in Syria"
Both sides accused the other of breaking the ceasefire.
Activists and fighters trapped in the opposition's last sliver of territory said pro-government forces had struck their district with dozens of rockets.
Russia, an ally of President Assad that has been backing up his push into the city, accused the rebels of "resuming the hostilities" at dawn.
The defence ministry in Moscow said Syrian government forces had repelled their attacks and was continuing its operation to quash their resistance.
Russian foreign minister Sergei Lavrov said the resistance was likely to end in the next two or three days.
Syrian activists spoke of "intense shelling", with some accusing Iranian militias allied to Mr Assad.
Activist from Aleppo city, Ismail Alabdullah, posted a video on Twitter this morning in which heavy bombing could be heard:
Activists said fighter jets had also resumed bombing raids but it is not known whether they were Syrian or Russian.
The UN said on Tuesday it had "credible reports" that civilians had been shot in the city, once Syria's largest and a thriving commercial and cultural hub.
Later in the day, an emergency UN Security Council meeting turned into an exchange of insults, with the US envoy lashing out at Syria, Russia and Iran.