The United Nations envoy on Syria, Staffan de Mistura, called on the US and Russian Federation to salvage the cease-fire they brokered this month.
A deepening rift has opened up between the West and Russian Federation amid angry exchanges at the United Nations over the failure to halt the fighting in Syria's bloody civil war.
Russia's Ambassador Vitaly Churkin conceded that the surge in violence over the past days meant that "bringing a peace is nearly an impossible task now".
Some U.S. intelligence officials believe that Russian President Vladimir Putin is taking advantage of Obama's refusal to intervene militarily in Syria and his lame duck status to seize as much territory as possible before the new U.S. president takes office.
Mr Shorten said Labor condemned the deliberate targeting of hospitals, water plants and unarmed civilians and such attacks must cease immediately.
Britain's ambassador to the United Nations has walked out of an emergency session of the Security Council, accusing Syria's representative of showing no interest in halting the country's bloody civil war.
Britain's United Nations ambassador, Matthew Rycroft, said the US and Russia's attempt to create peace in Syria is "very, very near the end of its life". -Russian talks failed to revive a cease-fire.
U.S. President Barack Obama has called such action a red line for his country.
US Ambassador Samantha Power said the current happenings in Aleppo are "apocalyptic".
In the central Syrian city of Homs, meanwhile, a second group of rebel gunmen and their families began evacuating from an opposition neighborhood. "Especially at night, the bombardment intensifies, it becomes more violent, using all kinds of weapons, phosphorous and napalm and cluster bombs", Mishal said. "We have proven this a few times before", Mistura said. "These bombs are not busting bunkers; they are demolishing ordinary people looking for any last refuge of safety".
He said the best way to force Moscow to pull back would be to shame it in the court of public opinion.
Children stand in front of the bullet-riddled facade of a building in the rebel-held Douma neighbourhood of Damascus, Syria September 25, 2016. The U.N. estimates 600,000 Syrians are trapped in different sieges.
Ban added that the airstrikes, incendiary weapons and bombs in densely populated areas may amount to war crimes.
Aid workers in the devastated Syrian city of Aleppo say Syria and its Russian allies stepped up their bombing campaign on rebel-held eastern parts of the city Monday, killing almost 100 people on the fourth consecutive day of mayhem and death.
Entering its sixth year, the Syrian civil war already has left some 250,000 people dead, uprooted more than 11 million and provided a base for Islamic State to launch and inspire attacks in the West. Hospitals in Aleppo were overwhelmed.
Hospitals are overwhelmed with casualties and medical workers are expecting numerous wounded to die from a lack of treatment, according to Mohammad Zein Khandaqani, a member of the Medical Council, which oversees medical affairs in the opposition areas.
He also urged the Security Council to press for a cessation of hostilities, weekly 48-hour pauses to deliver aid, and medical evacuations for several urgent cases in eastern Aleppo.
"The Assad regime, with direct participation of its ally Russian Federation and Iranian militias, has escalated its criminal and vicious attack on our people in Aleppo, employing a scorched-earth policy to destroy the city and uproot its people", a statement signed by 30 mainstream rebel groups said.
"It was hoped that they could turn over a simmering mess to the next president", said a US official.