CASTAIC, Calif. (KABC) -- Two Los Angeles County Sheriff's Department deputies were critically injured after a fire and possible explosion erupted Tuesday morning amid live ordnance at a training facility in Castaic, authorities said.
The training accident occurred about 9:30 a.m. in a mobile shooting range at the Pitchess Detention Center at 29340 The Old Road, just east of the 5 Freeway.
A spokesperson for the Los Angeles County Fire Department initially said four deputies were injured, two of them with minor injuries. However, officials later said that only two deputies sustained injuries and they were taken to Henry Mayo Newhall Hospital in Valencia.
Video from AIR7 HD showed firefighters dousing a burning tractor-trailer with water from a fire hose within the perimeter of the detention center. An armored vehicle was parked alongside the trailer, which housed the shooting range. Deputies and firefighters were seen holding protective shields along with the fire hose.
WATCH: LA County sheriff provides update after 2 deputies critically hurt in fire at training facility
The cause of the incident was under investigation.
After learning of the incident, Los Angeles County Sheriff Robert Luna made his way to the Valencia medical center where the injured deputies were hospitalized. Luna held a 1 p.m. news conference at the hospital, where he was joined by a Fire Department official and hospital spokesmen.
Even as the afternoon news conference was being held, firefighters continued to battle the active fire at the detention facility, Luna said. Their efforts were hampered by concern over unexploded ammunition at the scene.
The two deputies remained hospitalized in critical but stable condition after suffering burn injuries, a doctor said, declining to provide additional details due to medical privacy laws. They have since been transferred to L.A. County + USC Medical Center for ongoing treatment.
"In general terms, I can't give the specific details of the injuries, but in general terms, for any fire accident or injury, we've been treating burn injuries," said Chief of Staff Dr. Louie-Marc Contreras.
Luna declined to identify the deputies by name. One of them was a 21-year veteran of the department assigned to sheriff's North County Correctional Facility; the other was a 17-year-veteran assigned to the Sylmar courthouse.
Out of an abundance of caution, all mobile shooting ranges across L.A. County were temporarily closed while investigators worked to determine a cause, Luna said. The county also has outdoor ranges available.
"Due to the early stage of the investigation and the potential hazards posed by unspent ammunition in the vicinity of the mobile range, investigators will enter the area only when it is deemed safe," the Sheriff's Department said in a statement. "The investigative process will resume once the materials and debris have sufficiently cooled."