As reported by Censor.NET citing Reuters, Army Lieutenant General Stephen Townsend told a Pentagon news briefing on Wednesday.
"Yesterday, we had some Russian aircraft and (Syrian) regime aircraft bomb some villages that I believe they thought were held by ISIS, yet they were actually - on the ground - were some of our Syrian Arab coalition forces," the top U.S. commander in Iraq said using an acronym for the Islamic State militant group.
The villages were close to al Bab and about 15 or 20 km (10 to 12 miles) from Manbij city, Townsend said.
U.S. forces in the area, four or five km (2-1/2 to three miles) away, observed the strikes and the U.S. military called their Russian counterparts through an emergency line, after which the bombing stopped, Townsend said.
"Some quick calls were made through our deconfliction channels and the Russians acknowledged and stopped bombing there," he added.
The United States and Russia have a channel for avoiding each other in the crowded airspace over Syria. In 2015, they agreed to create a ground communication link and outline steps their pilots could take to avoid an inadvertent clash over Syria.
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