A file picture of the victim, Emily Keyes. (AP)

Denver, Sept. 28 (Agencies): A gunman took two girls hostage at a Colorado high school yesterday and sexually assaulted and shot one of them before killing himself when police stormed the classroom where he was barricaded.

The wounded girl, Emily Keyes, 16, was rushed by helicopter to a hospital in nearby Denver but died there. Her classmate and fellow hostage was apparently unhurt.

The shooting drew comparisons to the 1999 Columbine killings that took place 50 km away in Littleton, Colorado. At Columbine High School, two students shot and killed 13 people and wounded 21, then committed suicide.

The 53-year-old gunman, Duane Morrison of Denver, walked into Platte Canyon High School in the small mountain town of Bailey shortly before noon and opened fire. He initially took six girls hostage but later released four of them.

“We tried talking and had some success,” Park County sheriff Fred Wegener said.

“He started to release hostages, but eventually he gave us a deadline of 4 ’clock (to back off) and ceased talking to negotiators, at which time we decided a tactical solution needed to be done. Entry was made, the suspect shot one of the hostages and then shot himself.”

His connection to the school was not immediately clear and the police said they had not found a motive. The incident prompted the evacuation of hundreds of students.

Morrison had told the police he had explosives, but none were found at the scene. Two weapons — a revolver and a semi-automatic pistol — were found on Morrison when his body was removed. He had no known connections with the area, and a “very minor” criminal record, Wegener said.