Power angrily denounced the Russian call for the UN meeting as a stunt.
Power said "even by Russia's standards, tonight's stunt -- a stunt replete with moralism and grandstanding -- is uniquely cynical and hypocritical."
If US-led coalition airstrikes did hit Syrian forces Saturday, it was unintentional and Washington regrets any loss of life, she said before proceeding to list atrocities she said the Syrian regime has perpetuated during the five-year civil war.
"Since 2011, the Assad regime has been intentionally striking civilian targets with horrifying, predictable regularity. They have besieged civilian areas, prevented life-saving aid from reaching people who are starving to death, and dying of illnesses that could be treated with basic medicine."
Whether the diplomatic squabbling will cause the ceasefire to fall apart is unclear.