The pilot of the plane, who was the only occupant of the aircraft, was ejected before the crash and safely landed at a nearby airfield where a parachute was spotted. He is believed to be OK, Major Perry Covington, a spokesman at March Reserve AFB, said.
Firefighters responded to the wreck around 3:40 p.m. The plane crashed at the end of the runway and into a warehouse, where a small fire temporarily ignited and was contained by the building's sprinkler system.
Images from KABC-TV showed a large hole on the roof of the building.
Capt. Fernando Herrera with Cal Fire and the Riverside County Fire Department said the first fire unit to arrive confirmed the military aircraft crashed into the tilt-up building.
Authorities conducted a search and the people inside the building were evacuated. Herrera said 12 people were treated and hosed down for exposure to debris from the plane crash before being transported. No major injuries were reported in the incident.
Fire officials and other agencies worked together to extend an evacuation zone to about 4,000 feet from the area of impact.
A photo from inside the building appeared to show part of the plane sticking out of the rubble. Jeff Schoffstall said he was working when he heard the plane come dangerously low to the ground before it made a loud noise. He posted video from inside the building.
Another employee spoke to KABC-TV about witnessing the aftermath of the crash.
"It was almost to the point where I had to cover my ears, and next thing you know I just hear this explosion," said witness Daniel Gallegos. "I turn around to the back of the building and I just seen a burst of flames and just the ceiling start falling through every part of the building. In a matter of seconds, my ankles were filled with water."
A hazardous team was to make entry into the building to secure whatever is left of the plane, Herrera said.
In a brief statement, officials said the pilot was conducting a training mission for North American Aerospace Defense Command, or NORAD.
Reports of bombs and ammunition on board the plane were not confirmed by the military.
The pilot is part of the 144th Fighter Wing, an Air National Guard unit based in Fresno.
The aircraft belongs to the South Dakota Air National Guard in Sioux Falls. The United States Air Force Reserve said in a press release that the plane was conducting a training mission for the North American Aerospace Defense Command at the time.
An investigation into the cause of the crash is ongoing.