A pilot ejected moments before an F-16 fighter jet armed with live ammunition crashed into a warehouse just outside March Air Reserve Base in California, military officials said.

The ammo was needed as part of an alert mission to protect US skies post-9/11 and it has now been secured and will be 'disposed of in accordance with Air Force policies and regulations'.

'The NORAD alert aircraft was flying with a standard armament configuration as part of its Operation Noble Eagle commitments,' a defense official said Friday.

An F-16 is capable of carrying two bombs but it was likely carrying air-to-air missiles for the operation. The exact setup cannot be revealed.

A pilot ejected moments before an F-16 fighter jet that had live ammunition on board crashed Thursday into a warehouse just outside March Air Reserve Base in California

'Every effort is being made to ensure that the public’s safety is being met,' vice commander of the 452nd Air Mobility Wing at March Air Reserve Base, Col. Tom McNamara, said at a news conference Friday.

'Due to the nature of this type of an incident the recovery process is extremely involved. 'Our [explosive ordnance] disposal team is on site and is working through the situation at this time.'

Base officials say the plane may have experienced a 'possible hydraulic failure.'

The jet pancaked onto the roof of the 500,000-sq-ft building, causing a fire that triggered the on-site sprinkler system, containing the flames, reports said.

A fire official said it's 'a miracle' there was no explosion.

The pilot was not hurt and there were no immediate reports of injuries on the ground in Riverside County, said Maj. Perry Covington, director of public affairs at the base.

'Next thing I know I just hear this explosion and turn around to the back of the building, and I just seen a burst of flames and just the ceiling started falling through every part of the building,' Daniel Gallegos told KABC-TV.

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

The pilot was not hurt and there were no immediate reports of injuries on the ground, said Maj. Perry Covington, director of public affairs at the base

The pilot ejected and parachuted to safety before the Air National Guard fighter plane hit the warehouse in an industrial area across the freeway from March Reserve Air Base on Thursday afternoon.

He was taken to a hospital for evaluation. In total, a dozen people were hosed off for exposure to debris before being taken to hospitals for evaluation and treatment of minor injuries, state fire Capt. Fernando Herrera said.

Gallegos said he believed a co-worker was struck by something, possibly a falling sprinkler. Herrera said there were no major injuries.

Television news showed a large hole in the roof and sprinklers on inside the building about 65 miles (105 kilometers) east of Los Angeles.

Cellphone photos and video from inside showed what appeared to be the tail of the plane buried in twisted metal and piles of cardboard boxes.

A large area around the warehouse was evacuated and nearby Interstate 215, which runs between the base and warehouse, was shut down until crews could render the jet's weaponry and ordnance safe.

The pilot, believed to be the only person on board the jet, was being medically evaluated, according to the Riverside County Sheriff's Office. The F-16 is assigned to the Air National Guard, officials said

'Every effort is being made to ensure that the public’s safety is being met,' vice commander of the 452nd Air Mobility Wing at March Air Reserve Base, Col. Tom McNamara, said Friday

'As long as the aircraft is here, we are considering it a viable and dangerous area and we're taking the precautions necessary,' Herrera said late Thursday night.

The air base commander, Col. Melissa Coburn, declined to describe the aircraft's armament.

The crash happened during a training mission, March Air Reserve Base Deputy Fire Chief Timothy Holliday said.

'The pilot was having hydraulic problems,' Holliday said. 'He started losing control of the aircraft.'

The jet's cockpit canopy was on a runway, and a parachute had settled in a nearby field.

The jet didn't cause a major fire or explosion, which was 'a miracle,' Holliday said.

The F-16 was on a training mission under the direction of the North American Aerospace Defense Command. The pilot is from the 144th Fighter Wing, an Air National Guard unit based in Fresno, and the F-16 belongs to the South Dakota Air National Guard in Sioux Falls.

The base is home to the Air Force Reserve Command's Fourth Air Force Headquarters and various units of the Army Reserve, Navy Reserve, Marine Corps Reserve, California Air National Guard and California Army National Guard.

A red parachute was left by the pilot who ejected before his F-16 fighter jet crashed