July 12, 1999:
A gunman walked into a house in Atlanta, Georgia, and shot dead two women and three children before killing himself. An 11-year-old boy was injured.
April 20, 1999:
Two teenagers, Eric Harris (18) and Dylan Klebold (17) killed 12 of their classmates and one teacher in a Columbine High School, Littleton, Colorado.
Another 23 students were injured. The pair later shot themselves, having left booby-trapped devices.
May 21, 1998:
Two teenagers were fatally shot and more than 20 people hurt when a 15-year-old boy allegedly opened fire at a high school in Springfield, Oregan. His parents were later found dead at home. The boy is awaiting trial.
May 19, 1998:
Three days before his graduation an 18-year-old pupil allegedly opened fire in a carpark at a high school in Fayetteville, Tennessee, killing a classmate who was dating his former girlfriend. He is also awaiting trial.
April 24, 1998:
A science teacher was shot dead in front of pupils at a graduation dance in Edinboro, Pennsylvania. A 14-year-old pupil is awaiting trial.
March 24, 1998:
Four girls and a teacher were shot dead and 10 people wounded during a false fire alarm at a middle school in Jonesboro, Arkansas when two boys aged 11 and 13 opened fire from the woods.
Both were convicted of murder and can be held until they are 21.
December 21, 1997:
Three students were killed and five others wounded in a hallway at Heath High School in West Paducah, Kentucky. One girl was left paralysed.
A 14-year-old pupil pleaded guilty but mentally ill to murder and is serving life in prison.
October 1, 1997:
A 16-year-old boy in Pearl, Mississippi, was accused of killing his mother, and then going to his high school and shooting nine pupils, two fatally.
He was sentenced to life in prison. Two others await trial on accessory charges.