The unprecedented strike was initially reported by the Syrian Democratic Forces, an alliance of Kurdish and Arab fighters supported by Washington. The SDF accused Russian warplanes of bombing its fighters for the first time in the complex war, though Russia's military spokesman denied targeting the group.
"This is not possible. Why would we bomb them?" military spokesman Igor Konashenkov told AFP at Hmeimim, Moscow's main base for its air operations in Syria in support of President Bashar al-Assad's government.
A statement later by the coalition dismissed the Russian denial. "Russian munitions impacted a location known to the Russians to contain Syrian Democratic Forces and coalition advisers. Several SDF fighters were wounded and received medical care as a result of the strike," the coalition statement said.