The worst mass-shootings of the past 30 years:
April 16, 2007 – Virginia Tech shooting leaves 32 people dead after student Seung-hui Cho opens fire on campus, before committing suicide.
December 14, 2012 – Newtown school in Connecticut targeted by Adam Lanza, with 27 dead including Lanza.
October 16, 1991 – Killeen, Texas shooting sees George Jo Hennard crash his pickup truck into a Luby’s cafeteria and begin firing, killing 22 people before taking his own life.
July 18, 1984 – San Ysidro, California sees 21 killed at a McDonald’s by an unemployed security guard James Oliver Huberty, who was then fatally shot by a police sniper.
December 2, 2015 – San Bernardino shooting leaves 14 dead at a community centre. Syed Farook and his wife Tashfeen Malik die in police shootout.
November 5, 2009 – Fort Hood in Texas attacked by Maj. Nidal Malik Hasan, an Army psychiatrist, and 13 killed.
April 3, 2009 – Binghampton immigration center in New York state attacked by Jiverly Voong, who kills 13.
April 20, 1999 – Columbine High School students Eric Harris and Dylan Klebold kill 13 before taking their own lives.
July 20, 2012 – Colorado cinema shooting leaves 12 dead as James Holmes opens fire during Batman screening.
September 16, 2013 – Washington Navy Yard becomes scene of running battle as Aaron Alexis, a Navy contractor, kills 12.
June 18, 2015 – Charleston prayer meeting attacked by Dylann Roof, leaving nine dead.