The incident quickly sparked one of the most hostile diplomatic exchanges between Washington and Moscow in recent years. Russia, after calling an emergency meeting of the UN Security Council, suggested that the strike was "not accidental" and that it was designed to derail the deal.
Russia's UN ambassador, Vitaly Churkin, also said the strike could be evidence of US support for Isis and an al-Qaeda affiliate fighting the Syrian Government, which the United States has sought to help oust.
Churkin spoke outside the Security Council chamber after his US counterpart, Samantha Power, appeared before reporters as the meeting was starting, scornfully calling the closed-door session a Russian "stunt". The Syrian regime, assisted by Russia, has tortured and bombed its people, Power said.
"And, yet, in the face of none of these atrocities has Russia expressed outrage, nor has it demanded investigations, nor has it ever called for . . . an emergency meeting of the Security Council. Seriously? And they're calling this emergency meeting? Really? Because of a single airstrike . . . in error . . . which we have quickly called for investigating?"
Churkin, who stalked out of the meeting as Power entered, said that he had never, "in all my years in international life, over 40 years," seen "such an extraordinary display of American heavy-handedness as we are witnessing today". He described Power's remarks as "demagoguery of the highest order".