Three children and one adult were killed in a shooting at an elementary school in Bend, Oregon, on Thursday, US media reported, citing sources. At least two people were taken to hospital following the incident at Silver Rail Elementary School.Police received a 911 call at 12.59pm reporting that an unknown man had fired a shot into a car outside the school. Within minutes, further emergency calls reported that a person had entered the school and started shooting.The attacker was shot and killed inside the school, police said. However, it was not immediately clear who had shot the suspect. Sheila Miller, spokesperson for the Bend Police Department, said it “may have been a bystander”.Authorities initially did not disclose the number of casualties. “We don’t have a number at this point. We know children are among the victims,” Miller said during a media briefing. The condition of those taken to hospital was not immediately known.Police arrived at the scene shortly after receiving the initial call and began evacuating people from the school. “We’re in the process at this time of going room by room and evacuating each of the people who are in that school. … This is the kind of thing we never want to see happen in Bend. It’s devastating,” Miller said, pausing to control her emotions.Silver Rail Elementary School was placed under lockdown, while the Bend-La Pine school district established a reunification point for families to collect their children.“We are stunned and heartbroken by this senseless tragedy,” Bend-La Pine Schools Superintendent Steven Cook said in a statement. “We extend our deepest sympathy to the families and to everyone affected by this violence. No words can adequately express the grief our community is experiencing.”The school, which serves children from kindergarten through fifth grade, had 459 enrolled students as of last year, according to the Oregon Department of Education.