One student has died after a gunman opened fire at Southern California high school.
The suspect is now in custody after the incident at Saugus High School in the city of Santa Clarita, around 30 miles from Downtown Los Angeles.
Henry Mayo Newhall Hospital tweeted that it had received several patients in a critical condition and confirmed the death of the female student.
Local schools have been placed in lock down after the shooting was reported.
Officers tweeted alerts to help students locate members of their family, however they said the situation is "still very active".
A process of interviewing those who were at the scene is now taking place.
Resources have been dispatched from across California to assist local officers.
Undersheriff Tim Murakami tweeted: "LASD has a large response which includes SWAT.
"Our mission is to not only locate and arrest the suspect but protect others from harm. Please pray for the recovery of the victims and the safety of the responding deputies."
There have been more than 300 mass shootings in the United States of America since the start of 2019, set against a backdrop of calls for strong gun laws.