US-led coalition air strikes reportedly killed dozens of Syrian soldiers on Saturday, endangering a US-Russian brokered ceasefire and prompting an emergency UN Security Council meeting as tensions between Moscow and Washington escalated, Reuters reported.
The United States military said the coalition stopped the attacks against what it had believed to be Islamic State positions in northeast Syria after Russia informed it that Syrian military personnel and vehicles may have been hit.
The United States relayed its "regret" through the Russian government for what it described as the unintentional loss of life of Syrian forces in the strike, a senior Obama administration official said in an emailed statement.
The 15-member Security Council met on Saturday night after Russia demanded an emergency session to discuss the incident and accused the United States of jeopardizing the Syria deal.
The US ambassador to the United Nations, Samantha Power, chastised Russia for the move.
"Russia really needs to stop the cheap point scoring and the grandstanding and the stunts and focus on what matters, which is implementation of something we negotiated in good faith with them," Power told reporters before the meeting.
She said the United States was investigating the air strikes and "if we determine that we did indeed strike Syrian military personnel, that was not our intention and we of course regret the loss of life."
When asked if the incident ended the Syria deal between Moscow and Washington, Russia's UN Ambassador Vitaly Churkin said: "This is a very big question mark."
"I would be very interested to see how Washington is going to react. If what Ambassador Power has done today is any indication of their possible reaction then we are in serious trouble," Churkin told reporters.
Moscow cited the strikes, which allowed Islamic State fighters to briefly overrun a Syrian army position near Deir al-Zor airport, as evidence that the United States was helping the jihadist militants.