The official response from U.S. Central Command released immediately afterward: Feb. 8, 2018 – Release # 20180208-01 – FOR IMMEDIATE RELEASE:
The bottom line is Bashir Assad, Russia and Iran are working together in Syria to keep Assad in power. A military force within of that nexus, mostly paid Russians, attacked a U.S. protected compound with tanks, artillery, mortars and rockets.
The U.S. responded with overwhelming air power (drones, B-52 bombers, F-15 fighter jets, Apache helicopters and AC-130 gun ships), raining down precision-guided munitions upon the enemy assault battalion (300 – 500), while disabling their communications capability, for approximately three hours. When the dust settled around 200 Russians were dead and hundreds wounded.