US shootings timeline in the past two decades

-- Killeen, Texas, October 1991: A man shoots dead 22 people in a restaurant and then kills himself.

-- Littleton, Colorado, April 1999: Two teenage boys shoot and kill 12 students and a teacher at Columbine High School before killing themselves.

-- Atlanta, Georgia, July 1999: A stock market trader goes on a day-long shooting rampage, killing 12 people, including his wife and two children, before taking his own life.

-- Red Lake, Minnesota, March 2005: A teenage boy kills two people at his grandfather's home on an Indian reservation and then goes to his local high school where he kills seven others before committing suicide.

-- Blacksburg, Virginia, April 2007: A student goes on a rampage at Virginia Tech, killing 32 people before committing suicide.

-- Omaha, Nebraska, December 2007: A 19-year-old man armed with an assault rifle shoots dead eight people in a shopping mall and then kills himself.

-- Covina, California, December 2008: A man dressed in a Santa Claus suit opens fire at a family party and then sets fire to the house. Nine people are killed. The gunman commits suicide.

-- Geneva County and Coffee County, Alabama, March 2009: In a shooting spree that tears through several towns, a 28-year-old unemployed man kills 10 people, including his mother and a toddler. He then kills himself.

-- North Carolina, March 2009: A heavily-armed gunman shoots dead eight people, many elderly and sick patients, in a North Carolina nursing home.

-- Binghamton, New York, April 2009. A gunman shoots dead 13 people at a civic center for immigrants.

-- Fort Hood, Texas, November 2009. US army psychologist Major Nidal Hasan opens fire at his military base, killing 13 people and wounding 42.

-- Manchester, Connecticut, August 2010: A man who complained of racism at the beer warehouse where he works goes to the facility and shoots dead eight people. He then kills himself.

-- Seal Beach, California, October 2011: A man angry over a child custody ruling opens fire at the hairdressing salon where his ex-wife works, killing her and seven other people.

-- Oikos, California, April 2012: A male nursing student methodically kills seven people at a Christian university.

-- Aurora, Colorado, July 2012: A man kills 12 people when he opens fire at a movie theater showing a late-night premiere of a Batman film in a suburb of Denver.

-- Newtown, Connecticut, December 2012: A young man kills 26 people, including 20 children at Sandy Hook elementary school. He then commits suicide.

-- Miami, Florida, July 27, 2013: A gunman shoots dead six people in a shooting rampage in an apartment building before being killed by police.