A world-stunning shooting rocked Sandy Hook Elementary School in the US state of Connecticut on Friday, leaving 20 children and eight adults dead.

The following are major school shootings in the United States since 1999:

- April 2, 2012: In the state of California, a man killed seven people and wounded three others at Oikos University in Oakland.

- February 14, 2008: In the state of Illinois, a gunman broke into Northern Illinois University and opened fire randomly at more than 160 students and teachers, killing six people and wounding more than 10 others before shooting himself dead.

- April 16, 2007: In Virginia, a 23-year-old student from South Korea went on a shooting spree at Virginia Tech University in Blacksburg, killing 32 people and wounding 15 others before killing himself. It was the deadliest campus shooting in US history.

- October 2, 2006: In the state of Pennsylvania, a gunman killed five girl students at an Amish school before killing himself.

- March 21, 2005: In the state of Minnesota, a 16-year-old student shot dead five students, a security guard and a teacher at Red Lake High School before killing himself during a shootout with police.

- April 20, 1999: In the state of Colorado, two male students armed with assault rifles shot dead 12 other students and a teacher in a rampage at Columbine High School and then killed themselves.