Colorado school shooting: 'I heard two loud bangs'
14 December 2013 Last updated at 02:00 GMT
A witness has described seeing a student with a gun enter a Colorado school, where he shot and injured at least one person before apparently fatally shooting himself.
Fabian Llerenas described alerting security to the incident at Arapahoe High School in Centennial, before hearing two loud bangs.
Friday's incident comes one day before the first anniversary of the shooting at Sandy Hook elementary school in Connecticut.