An explosion early Friday at a law enforcement training facility in Los Angeles that left three people dead was being investigated as a possible training accident, officials said.

The explosion was reported around 7:30 a.m. at the Biscailuz Training Facility, said Los Angeles County Sheriff's Department spokesperson Nicole Nishida. Tragically, she said, three members of the department died.

It was not immediately known what caused the explosion or what the department members were doing at the time.

An early line of the investigation was looking at a possible training accident, according to a law enforcement official briefed on the matter who was not authorized to discuss the matter by name and spoke to The Associated Press on condition of anonymity.

Attorney General Pam Bondi in a post on X said it "appears to be a horrific incident." She said federal agents are at the scene to learn more.

"Please pray for the families of the sheriff's deputies killed," Bondi wrote.

Arson investigators from the Bureau of Alcohol, Tobacco, Firearms and Explosives, the Los Angeles Fire Department and members of the Los Angeles Police Department bomb squad were assisting at the training facility, Los Angeles Mayor Karen Bass said in a post on X.

California Gov. Gavin Newsom's office said he's been briefed and that the Governor's Office of Emergency Services is in contact with the Sheriff's Department and closely monitoring the situation.

Aerial footage from KABC-TV shows the explosion happened in a parking lot filled with sheriff patrol cars and box trucks.