Rebel fighters and civilians had been due to leave early on Wednesday, but the ceasefire collapsed.
Rebel groups said late on Wednesday that evacuations would take place in the coming hours.
But there has been no confirmation so far from Russia, that helped negotiate the previous deal.
News agencies reported that the ceasefire would come into effect late on Wednesday, with evacuations to follow early on Thursday.
Under the first evacuation deal brokered by Russia and Turkey, civilians and rebels from eastern Aleppo were to be allowed to go to rebel-held areas in northern Syria.
Fighting ceased late on Tuesday, but evacuations scheduled for 05:00 (03:00 GMT) on Wednesday did not go ahead, and buses left empty.
The breakdown of the deal was attributed to demands from the government side.
Hours later, air strikes resumed over rebel-held territory, where at least 50,000 civilians remain.
The UN said raids by the Syrian government and its allies on an area "packed with civilians" most likely violates international law.
Zeid Raad al-Hussein, the UN High Commissioner for Human Rights, said the Syrian government had "a clear responsibility to ensure its people are safe".
In a statement, he said: "The way this deal was dangled in front of this battered and beleaguered population - causing them to hope they might indeed live to see another day - and then snatched away just half a day later is also outrageously cruel."
Meanwhile, the BBC has learned that Western forces are using satellites and unmanned aircraft to gather evidence of possible war crimes in Aleppo and elsewhere in Syria.