Police in Colorado are responding to a shooting in Arapahoe High School, in the Denver suburb of Centennial.
Two students were reported to have been shot, as information of the incident emerged at about 1pm MT (8pm GMT) on the eve of the 1 year anniversary of the Sandy Hook shootings.
All schools in the Littleton area were been placed on lockdown as a precautionary measure, but are now lifting the lockdowns.
One of the victims, a student at the school, confronted the suspect, and was subsequently shot. The Associated Press reported of his condition on Twitter:
BREAKING: Hospital spokesman: 1 student in critical condition after Colo. high school shooting reports - https://twitter.com/AP
Local media in Denver reported that the gunmen, who is suspected to be a student at the school, was looking for a specific teacher. 9News Denver said this on Twitter:
Local police later said in a news briefing that the suspected gunman had been found dead of a self-inflicted gunshot wound.
UPDATE: A 15 year old girl remains in a critical condition in hospital after being shot at Arapahoe High School, the Arapahoe County Sheriff Grayson Robinson said in a news conference earlier. Two other students who were injured in the gun attack have been released from hospital. Worried parents have also been reunited with their loved ones.
The school has said that the ID of the shooter is known to investigators, and that preliminary information suggests that it was an attempted revenge attack on a school teacher.