HOUSTON - US Air Force said a drone crashed on Friday at a national park in New Mexico during a training mission.

The unmanned QF-4 Drone crashed Friday morning at White Sands National Monument near Holloman Air Force Base in west New Mexico, local media KOB quoted base officials as saying.

The monument had been closed in advance to the test mission and would remain closed until further notice, according to the report. There was no threat to the public at this time.

The cause of the crash was not immediately known, and base officials were investigating.

The base, home of the 49th Wing of the US Air Combat Command, provides combat-ready airmen, F-22 Raptors, and trains MQ-1 Predator and MQ-9 Reaper pilots and sensor operators.

It is also home to the world's longest, at 50,188 feet (almost 16 km), and fastest, approaching 10,000 feet per second (3,050 m/s, Mach 9), test track.