Two people were injured in a shooting at a school in the US state of Colorado on Friday, local media reported, citing police detailing the "active" situation.
Arapahoe High School in Centennial, just outside Denver, was put on lockdown as were other schools in the area, reports said.
The Denver Post also cited reports of a fire at the school in Centennial, near the scene of last year's Aurora movie theater shooting that killed 12 people.
NBC television affiliate 9News said nobody was immediately taken into custody. Officers said the incident was an "active shooter situation."
Live television pictures showed orderly groups of students gathered on an athletics track on the the edge of a snow-covered field apparently next to the school.
Parents of students at the school were asked to gather at a nearby church, the Araphoe County Sheriff's department said on its Twitter feed.
A media briefing was scheduled for 1:45 pm (2045 GMT), it said.
The school has over 2,200 students and 70 classrooms.
It is part of the Littleton school district, to which Columbine High School -- scene of the 1999 shooting by two students which killed 13 -- also belongs.
The incident comes a day ahead of the first anniversary of the Newtown, Connecticut shooting in which a mentally unstable gunman killed 26 people in the Sandy Hook elementary school, including 20 young children.
That shooting re-ignited America's perennial debate over gun control, which is triggered every time there is a major shooting incident.