Three deputies were killed on Friday morning after an explosion at a Los Angeles County Sheriff's Department facility, the department confirmed. The explosion was reported at about 7:27 a.m., according to the L.A. County Fire Department. In a statement, Attorney General Pamela Bondi said federal agents were at the scene.

It was not immediately clear what caused the blast at the Los Angeles County Sheriff’s Department’s Biscailuz Training Academy center. No one else was injured, officials said.

An explosion early Friday killed three people and is being investigated at least preliminarily as a possible training accident, according to a law enforcement official briefed on the matter who spoke to The Associated Press on condition of anonymity.