Ambassador Samantha Power was speaking at the UN security council
There appears to be in sign of any end to the Syrian conflict with all sides pointing the finger at each other instead of working to achieve peace.
Speaking at an emergency meeting of the UN security council, US ambassador Samantha Power said: "instead of pursuing peace, Russia and Assad make war. Instead of getting life-saving aid to civilians, Russia and Assad are bombing the humanitarian convoys, hospitals and first-responders who are trying desperately to keep people alive."
"Russia will argue today no doubt that these attacks are meant to fight terrorism and that the people killed in this offensive are terrorists or terrorist sympathisers. This is absurd."
"Eastern Aleppo remains underseige as we convene here today. It seems the only items making it into Aleppo these days are barrel-bombs and incendiaries that witnesses report seeing dropped by Assad's forces and Russian forces.
"Even now, we will continue to look for any way possible to restore the cessation of hostilities."
"What Russia is sponsoring is not counter-terrorism, it is barbarism. It is apocalyptic what is being done in eastern Aleppo," she concluded.
Earlier Russia's ambassador attacked Boris Johnson after he said Moscow's forces may be guilty of war crimes in Syria.
The British Foreign Secretary condemned the bombing of rebel held areas of Aleppo and has accused Vladimir Putin of encouraging the conflict.
The Russian Foreign Ministry's hit back saying that if anyone was guilty of war crimes, it was British forces in Iraq.