The US network Fox News has apologised for showing a man fatally shoot himself in the head on live television.

Fox News on Friday was covering a high-speed chase that began in Phoenix, Arizona, using a live helicopter shot.

After driving for dozens of miles into the desert, the motorist stopped and ran on to a dirt road. He then put a handgun to his head and fired.

TV anchor Shepard Smith later apologised to viewers for not cutting away. "We really messed up," he said.