An F-16 fighter jet being flown in routine training exercises has crashed into a commercial building at March Air Reserve Base in Southern California.

Base spokesman Major Perry Covington said the US Air National Guard aircraft went down about 8.30am on Friday (AEST) and slammed into a warehouse at the end of the base runway.

Footage obtained by a local television station Fox5 San Diego showed a warehouse worker inside the warehouse moments after the $40 million aircraft crash-landed.

“Holy [expletive] dude. That’s a [expletive] airplane; that’s a military airplane in our building,” he said.

Another warehouse worker Daniel Gallegos told KABC-TV: “Next thing I know I just hear this explosion and turn around to the back of the building, and I just [saw] a burst of flames and … the ceiling started falling through every part of the building”.

“I turned around, and my co-worker just told me to get, so I just made a run for it.”

Our @PhilBFox5 showing video from inside building near March Reserve Base in Riverside County shot by a worker moments after F-16 jet crashed through the ceiling…. @fox5sandiego pic.twitter.com/ihVYuhQIXg

— Kathleen Bade (@KathleenFOX5) May 17, 2019

Major Covington said the pilot managed to safely eject and no injuries were reported after it crashed through the roof of the building.

“The pilot did eject and the pilot is OK, and there are no other injuries at this time,” he said, adding he did not believe anyone was inside the warehouse when the crash occurred.

The Los Angeles Times reported the crash ignited a small fire, quoting a base fire official, and aerial footage of the accident scene showed a gaping hole in the roof of the building.

Here's the scene where an F-16 fighter jet crashed into a building near March Air Reserve Base in Riverside County. The 215 Fwy is shut down in both directions. Details: https://t.co/pIyQXcCorG pic.twitter.com/1uBVypn61a

— KTLA (@KTLA) May 16, 2019

The sprawling installation, located in Riverside County, California, about 105 km east of Los Angeles, is home to the Air Force Reserve 452nd Air Mobility Wing.

There are normally between 2000 and 6000 Air Force reservists and other personnel on base at any given time.

A section of Interstate 215, a major north-south route running through the base, was closed in both directions after the crash.

NBC reported the aircraft was carrying live ordnance at the time of the crash, prompting flight restrictions over the area.

It is not yet known what caused the pilot to eject.

Watch the moment the F-16 crashed through the warehouse roof courtesy dashcam footage from the nearby freeway.

Video of #F16 moments before it crashed through the roof of a California warehouse. Pilot ejected. pic.twitter.com/cwpY8B0bef

— Doug Dunbar (@cbs11doug) May 17, 2019

-with AAP