Three children and teacher killed by 16-year-old at Oregon primary school

Figure caption, "It's really hard to believe" - How Oregon primary school shooting unfolded

A 16-year-old has shot dead three children and a teacher at a primary school in the US state of Oregon before he was killed by a bystander, police said.

The suspect, who has not been named, forced his way into Silver Rail Elementary School in the city of Bend on Thursday afternoon by shooting at locked doors, Bend Police Chief Mike Krantz confirmed.

The teenager was shot dead by a community member who "pursued him into the school and engaged him", Krantz said. Police arrived three minutes later.

The three children killed were aged five, eight and 11. A seven-year-old and a 54-year-old teacher were taken to a hospital in a critical condition. It is unclear if the attacker had any links to the school.