Authorities say a second victim of a Los Angeles area high school shooting has died.

Los Angeles County Sheriff Alex Villanueva says a 14-year-old boy died at a hospital.

Earlier, a 16-year-old girl died from the shooting at Saugus High School in the city of Santa Clarita.

Authorities say a student gunman shot five students and then himself at around 7:30am in a school grounds.

His .45-caliber handgun was found with no bullets remaining when it was recovered.

Freshman Rosie Rodriguez said she was walking up the library stairs when she heard noises that “sounded like balloons” popping.

She realised they were gunshots when she saw other students running.