Syrian government officials on Monday accused the U.S.-led coalition of bombing a Syrian army encampment, killing three soldiers and wounding 13 others in what they described as "a heinous aggression."
U.S. officials quickly denied the accusation, which if true would mark the first time the coalition had targeted Syrian army units since its air campaign to roll back the advances of Islamic State militants began more than a year ago.
See the most-read stories this hour >>
Syria's Foreign Ministry issued letters to the United Nations Security Council and U.N. Secretary-General Ban Ki-moon condemning what it said was an attack Sunday night by warplanes of the U.S.-coalition on an army outpost in the northeastern city of Dair Alzour.
Aside from the casualties, the statement said, a number of army vehicles and other materiel were destroyed.
"The aggression on the military post hinders the efforts aiming to fight terrorism and reiterates that the U.S.-led coalition lacks seriousness and credibility in the fight against terrorism," the Syrian government said in the letter.
The Syrian army and Islamic State have been battling for control of Dair Alzour.
The U.S.-led Combined Joint Task Force responded Monday that four strikes were conducted on "ISIL [oil] wellheads" near Dair Alzour, referring to Islamic State by one of its acronyms. But coalition envoy Brett McGurk, in a post on Twitter, insisted there were no strikes within "55km [about 35 miles] of claimed incident on Syrian base."
"Reports of coalition involvement are false," he concluded.
U.S. officials, who requested anonymity because they were not authorized to speak publicly on the matter, suggested that an errant Russian military strike was responsible for the Syrian casualties.
The Syrian Observatory for Human Rights, a pro-opposition watchdog with a network of activists on the ground in Syria, confirmed that an attack occurred near the town of Ayyash, about seven miles northwest of Dair Alzour. The observatory put the number of wounded at 14.
Most of Dair Alzour province, where the city is located, was overrun by Islamic State during the extremist group's offensive through parts of Iraq and Syria last year. The oil-rich area has become the economic heartland of the group's so-called caliphate.
In recent weeks, coalition forces have actively targeted oil wells and infrastructure in the province in an attempt to deny the militants oil revenue.
The strike further ratchets up the tension between the coalition and an alliance that Russia has forged with Syrian President Bashar Assad and Iran. Moscow says its efforts are aimed at attacking Islamic militants, but the U.S. and its allies believe the Russian goal is to prop up Assad's government.
Turkish forces shot down a Russian warplane along the Syrian-Turkish border late last month. Turkey said the plane, which was conducting a bombing run on rebel groups operating in the area, was violating its airspace.
Bulos is a special correspondent.