The UN Security Council will hold urgent consultations on Saturday after US-led coalition air strikes hit Syrian military positions, diplomats said.
Russia requested the meeting, which is set to take place from 7:30 pm (2330 GMT).
“We demand Washington’s full and detailed explanation, and that must be made before the UN Security Council,” Russian foreign ministry spokeswoman Maria Zakharova said in Moscow.
Russia is “very concerned” by the strikes that “directly targeted the Syrian army, which has been consistently fighting the Islamic State group’s forces,” she added.
The bombing hit an army position in the east, near the IS-controlled town of Deir Ezzor, a Russian army statement said.
At least 62 soldiers were killed in the strike, according to Russian officials and a Syrian monitoring group.
“These strikes endanger everything that has been done so far by the international community” to reach peace in Syria, the Russian foreign ministry spokeswoman said.
Zakharova accused the United States of being “simply incapable of honoring its commitment” to distinguish between jihadists and Syrian mainstream rebels in the implementation of a ceasefire in force since Monday.
Earlier, a Russian army statement said “warplanes from the international anti-jihadist coalition carried out four air strikes today against Syrian forces surrounded by the Islamic State group in the Deir Ezzor air base.”
“Sixty-two Syrian soldiers were killed and a hundred others were injured in these strikes.”
American officials admitted the US-led coalition fighting the Islamic State (IS) group in Syria may have hit Syrian military positions.
“Coalition forces believed they were striking a Daesh fighting position,” a Pentagon statement said, using an Arabic acronym for the IS group.
“The coalition air strike was halted immediately when coalition officials were informed by Russian officials that it was possible the personnel and vehicles targeted were part of the Syrian military.”
The statement added that “coalition forces would not intentionally strike a known Syrian military unit.”
Syria’s conflict has killed more than 300,000 people and displaced half the country’s population since March 2011.