A television journalist and a nine-year-old girl were shot dead in the US state of Florida, allegedly by the same gunman who killed a woman earlier in the day in the area, the authorities said.

The 19-year-old suspect fatally shot a 20-year-old woman at about 11am on Wednesday in Pine Hills, a suburb west of Orlando in central Florida. About five hours later, he returned to the crime scene and opened fire on a Spectrum News 13 camera operator and a reporter as they stood near their vehicle.

He then entered a nearby home and shot a woman and her nine-year-old daughter, according to police, in the latest mass shooting in the country.