Details of the air mission over Syria were confirmed by a U.S. official not authorized to speak publicly because the details have not yet been formally announced.
C-17s, accompanied by fighter escort aircraft, dropped small arms ammunition and other items like hand grenades in Hasakah province in northern Syria to a coalition of rebels groups vetted by the US, known as the Syrian Arab Coalition.
All pallets successfully were recovered by friendly forces, a U.S. official said.