The explosion was reported about 7:30 a.m. at the Biscailuz Training Facility, Los Angeles County Sheriff’s Department spokesperson Nicole Nishida said. It was not immediately known what caused the explosion or what the deputies were doing at the time.

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.

A Friday blast at a Los Angeles County Sheriff’s Department training facility killed three members of its arson and explosives unit, marking one of the department's worst losses of life from a single incident,