Three people were killed in a helicopter crash in a rural area of Los Angeles County while filming for a new reality TV show for the Discovery Channel Sunday.
The helicopter crashed at about 3:40 a.m. at the popular filming location of Polsa Rosa Ranch in Acton, county fire dispatcher Robert Diaz said.
All three people aboard died. Their names weren't immediately released.
The show, listed on a filming permit as an untitled military-theme TV program, had not yet been aired or announced, Discovery's Laurie Goldberg said.
"A production company was shooting a show for Discovery Channel when this tragic accident occurred. We are all co-operating fully with authorities."
"Our thoughts and prayers go out to the families."
The show's production company, Eyeworks USA, best known for creating NBC's The Biggest Loser, also issued a statement expressing sympathies.
The company had been approved to use a helicopter for a reality TV show shooting at the ranch from Saturday afternoon until Sunday morning.
Records also showed Crossbow Helicopters received approval to participate in filming from the Federal Aviation Administration, according to reports.
The cause and other circumstances surrounding the helicopter crash are still unknown, Federal Aviation Administration spokesman Allen Kenitzer said.
News footage showed mangled wreckage in a rugged canyon area near Soledad Canyon Road, an area often used in film and TV due to its varied terrain.
It was the site of another industry death in 2012, when a 48-year-old crew member died of an apparent heart attack on the set of The Lone Ranger.