Russia and Syria say 62 Syrian soldiers killed by coalition aircraft near ISIL-held city of Deir Az Zor.

US-led coalition air raids 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 Washington and Moscow escalated.

The US military said that the coalition stopped its strikes against what it believed to be Islamic States of Iraq and the Levant (ISIL) group positions in the eastern city of Deir Az Zor on Saturday after Russia informed it that Syrian military personnel and vehicles may have been hit.

“We are investigating the incident,” Samantha Power, the US ambassador to the United Nations, told journalists as the emergency Security Council meeting, called by Russia, got under way in New York.

“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.”

If confirmed, it would mark the first known direct American strike on forces loyal to Syrian President Bashar al-Assad.

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Russia said that 62 Syrian soldiers were killed and at least 100 more wounded in strikes by “warplanes from the international anti-jihadist coalition”.

The Russian military said two F-16 and two A-10 jets flew into Syrian airspace from neighbouring Iraq to carry out the raids.

The UK-based Syrian Observatory for Human Rights monitoring group gave a toll of 83 soldiers killed, as it confirmed the strikes were US-led coalition raids.

A US military official speaking to the AFP news agency appeared to confirm the attack, saying “we believe about a half-dozen vehicles, including what we think was a tank, were struck as well as personnel who were out in the open”.

The Australian Department of Defence said on Sunday that its planes had participated in the strikes and offered condolences to the families of Syrian soldiers killed or wounded in the incident.

Russian ‘stunt’

Power accused Russia of pulling a “stunt” by calling for an emergency Security Council meeting to demand an explanation from the US. She said Moscow should instead demand a meeting with the Syrian government to press for peace.

“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.

Russian Ambassador to the UN Vitaly Churkin responded by accusing the US of violating agreements that it would not target Syrian positions and said the action was a “bad omen” for a US-Russian deal on halting the fighting in Syria.

Washington and Moscow reached an agreement in September that calls for a ceasefire, the delivery of aid and the joint targeting of the ISIL, also known and ISIS, and Jabhat Fateh al-Sham.

The ceasefire came into effect on Monday and has largely held, despite dozens of alleged violations.

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Al Jazeera’s senior political analyst Marwan Bishara said Moscow used the incident to underline the importance of communication between Russia and the US in military operations in Syria.

“What the Russians are saying today is you – the Americans – because you don’t want to coordinate on the ground these sorts of mistakes are going to happen more often. It’s quite foggy in terms of coordination on the ground. With the various violations of the ceasefire, you’re going to see more friendly type fire going on,” Bishara said.

US Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov are due on Wednesday to attend a special Security Council meeting on Syria, held on the sidelines of the UN General Assembly meeting.