Oregon Governor Tina Kotek praised the bystander who "heroically intervened" to stop further loss of life.

"Your actions carry a heavy emotional burden and I just want you to know that my thoughts are with you as well," she told a media briefing alongside other officials.

Police did not reveal any details about the "community member" who shot the teenager, but audio recordings of Emergency Medical Services dispatch suggest he was the parent of a pupil.

"Looks like the shooter has been neutralised, possibly shot by a father at the school. Not sure about patients at this time, the police are arriving," a staff member is heard saying.

A local newspaper reporter told BBC Radio 4's Today programme that the school was in lockdown during the shooting and that students were able to communicate with parents outside with their Apple watches.

Michael Kohn, a reporter with Bulletin newspaper, said the incident had left the parents stunned.

"This is a neighbourhood school. Parents are stunned. It's just something you don't expect to happen in Bend, Oregon. It's a mountain town," he said.

Teacher Kathy Sheil Smith described to CNN affiliate KPTV how she tried to keep the children calm after spotting the gunman approach the school.

"The looks on their faces was really hard to see," she said.

"Some kids were praying, some kids were consoling other kids. I'm sure that every teacher at the school thought 'Today is the day that I am going to die,'" she added.

Read More