Police were responding to reports of a shooting at a Colorado high school on Friday in which two people may have been wounded, local media reported.
The Denver Post newspaper reported a shooting and a fire at Arapahoe High School in Centennial, Colorado, citing a dispatcher with the Arapahoe County Sheriff's Office.
Arapahoe County Sheriff Grayson Robinson told the local ABC affiliate he believed there were two victims and that the shooter was still inside the school but gave no further details. Local KDVR television reported two people had been injured.
The Arapahoe County Sheriff's office confirmed to Reuters that officers were at the school but declined to give further details.
The incident comes a day before the first anniversary of the tragedy in Newtown, Connecticut, in which a gunman killed 20 children and six adults at Sandy Hook Elementary School.
Television images from the Colorado school show students running out of the building with their hands raised and gathering on a track field. Some students were shown being patted down after leaving the school.
A woman who answered the phone at a Yogurtland across the street said her store was being evacuated and dozens of police officers were at the school with guns drawn.
Phone calls to the Arapahoe High School were not answered. A spokesman for Littleton Public Schools, the district which administers the school, said the school had been placed on lockdown.
Centennial is a suburban community south of Denver, not far from the unincorporated community in nearby Jefferson County that is home to Columbine High School, where two students killed 13 students and staff there before shooting themselves to death in 1999.
Reporting by Dan Whitcomb, Steve Gorman and Alex Dobuzinskis; Writing by Dan Whitcomb; Editing by Cynthia Johnston, Sandra Maler and Gunna Dickson
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