Russian and Syrian regime attacks in the city have killed, maimed and injured hundreds of civilians, including children.
A top United Nations human rights official on Friday called the siege and bombing of Aleppo, which has caused heavy civilian casualties, "crimes of historic proportions."
Zeid Ra'ad al Hussein did not specifically name Russia, whose warplanes have carried out weeks of air strikes on the opposition-held part of Aleppo along with the Syrian regime air force, but his reference was clear.
Indiscriminate airstrikes by Govt forces & their allies responsible for overwhelming majority of civilian casualties https://t.co/TYdc4rXlh7— UN Human Rights (@UNHumanRights) October 21, 2016
"Armed opposition groups continue to fire mortars and other projectiles into civilian neighbourhoods of western Aleppo, but indiscriminate air strikes across the eastern part of the city by Government forces and their allies are responsible for the overwhelming majority of civilian casualties," Zeid said in a speech by video to a special session of the UN Human Rights Council.
He called on major world powers to set aside their differences and refer the situation in Syria to the prosecutor of the Hague-based International Criminal Court.
"The violations and abuses suffered by people across the country, including the siege and bombardment of eastern Aleppo, are simply not tragedies; they also constitute crimes of historic proportions," Zeid told the Geneva session.
Britain, along with the United States, requested the one-day session to set up a special inquiry on Aleppo.
"Russia, you are making the situation worse, not solving it," Tobias Ellwood, the British government minister for Africa and the Middle East, said in a speech to the Geneva forum.
"This is shameful, and it is not the action or leadership that we expect from a P5 nation," he said, referring to the five permanent members of the UN Security Council -- Britain, China, France, Russia and the United States.
Russian Ambassador Alexey Borodavkin accused Britain and its allies of "trying to save terrorists from being the target of strikes, allowing them to regroup and continue their barbaric acts."
Russia on Thursday offered an 11-hour unilateral ceasefire in Aleppo, saying it would allow civilians and those fighters who lay down their weapons to leave the city.
Paulo Pinheiro, chairman of the UN commission of inquiry on Syria, said that the panel would continue to document war crimes in Aleppo in an impartial way and urged the Bashar Al Assad regime to provide information on violations.
"Over a quarter of a million people have been besieged and subjected to withering daily air strikes for more than one month," Pinheiro said.
"Hospitals, markets, bakeries and water stations have all been targeted by aeroplanes flying overhead; many have been destroyed, amplifying the effect of the siege."