The jet slammed into the side of a commercial building off the base, on Van Buren Boulevard, about 3.45 p.m. on Thursday, March Air Reserve Base Deputy Fire Chief Timothy Holliday was quoted as saying.
The pilot was ejected and being medically evaluated.
"Multiple agencies responding. Please stay out of area and clear emergency vehicles," the department tweeted.
Details on the crash and the pilot's condition have not been disclosed. Authorities did not have details on any other injuries.