Three western powers, Britain, France and the United States blamed Russia over the worsening situation in Syria on Sunday during an emergency session of the UN Security Council on Syria.
The trio accused Russia for supporting the violence in the country to back his ally Syrian regime leader Bashar Al Assad.
The US ambassador to the UN, Samantha Power called Russia’s conduct in Syria as "barbarism", urging Moscow to halt the intense air strikes.
“Instead of pursuing peace, Russia and Assad make war," Power said. "What Russia is sponsoring and doing is not counter-terrorism. It is barbarism," she added.
According to Syrian Observatory for Human Rights, more than 124 people, mostly civilians, have been killed in the heavy bombardment of rebel-held eastern Aleppo since the army on Thursday announced an operation to retake the city.
"War crimes are being committed here in Aleppo," French Ambassador Francois Delattre said, calling for action to ensure the atrocities do not go unpunished.
Britain's envoy spoke of "a new hell" unleashed on Syrians with bunker-busting bombs and more sophisticated weaponry used in air strikes pummelling residential areas.
"It is difficult to deny that Russia is partnering with the Syrian regime to carry out war crimes," said British Ambassador Matthew Rycroft.
Britain, France and the United States had called for the urgent talks after days of intense diplomatic efforts to salvage a US-Russian ceasefire deal ended in failure at the weekend.
On Saturday UN Secretary-General Ban Ki-moon also said that he was "appalled by the chilling military escalation in the city of Aleppo, which is facing the most sustained and intense bombardment since the start of the Syrian conflict".
"Since the announcement two days ago by the Syrian Army of an offensive to capture eastern Aleppo, there have been repeated reports of airstrikes involving the use of incendiary weapons and advanced munitions such as bunker buster bombs," he continued.
Russia's Ambassador Vitaly Churkin conceded that the surge in violence over the past days meant that "bringing a peace is almost an impossible task now."
Churkin again laid blame for the failed diplomacy with the United States, accusing Washington of being unable to convince armed opposition groups that it backs on the ground to distance themselves from the Al-Qaeda-linked Nusra Front and abide by the ceasefire.
A US-Russian ceasefire deal that would have charted a way forward towards peace talks was broken by the "sabotage by the moderate opposition", he asserted.
Churkin however said that reviving the ceasefire was still a goal that Moscow could pursue if it was part of a "collective" effort on all sides.
Despite the recriminations, UN envoy Staffan de Mistura said a "tiny window of opportunity ... still exists" for Russia and the United States to help Syria.
He appealed for renewed efforts to allow Syria to "step away from the brink of more years of bloody conflict which risks to become even worse."
Residents said cluster bombs rained down on Saturday night on eastern parts of the city, where an estimated 250,000 people are living under a government siege.
At least 19 children were among those killed in the assault, which has included missile strikes, barrel bomb attacks and artillery fire, the Syrian observatory said.
"All night long they were dropping cluster bombs. I couldn't sleep until four in the morning," said 62-year-old Ahmed Hajar, who was out looking for bread in the Al-Kalasseh neighborhood.