Here are the worst mass shootings in American history, ranked by the number of people killed.
October 2, 2017 - At least 59 dead and 527 injured after a gunman fired at a concert from the 32nd floor of the Mandalay Bay hotel in Las Vegas.
June 12, 2016 - A gunman fatally shoots 49 people at gay nightclub Pulse before he is shot dead by police
April 16, 2007 - A gunman slaughters 32 people and kills himself at Virginia Tech, a university in Blacksburg, Virginia
SUTHERLAND SPRINGS, TEXAS
November 5, 2017 - More than 20 reportedly killed when a shooter opened fire at the First Baptist Church in Sutherland Springs near San Antonio.
Live: Gunman storms Texas church
December 14, 2012 - A man shoots dead his mother, then kills 20 children, six adults and himself at Sandy Hook Elementary School in Newtown, Connecticut
December 2, 2015 - A husband and wife kill 14 people at a workplace holiday party in San Bernardino in Southern California before dying in a shootout with police
April 20, 1999 - Two teenagers rampage through Columbine High School in Littleton, Colorado, shooting dead 12 students and a teacher and wounding more than 20 others before killing themselves
April 3, 2009 - A Vietnamese immigrant opens fire at an immigrant services centre in Binghamton, New York, killing 13 people and wounding four. He then kills himself
November 5, 2009 - An army major and psychiatrist opens fire at Fort Hood, a US Army base in Texas, killing 13 people. He is sentenced to death
September 16, 2013 - A former Navy reservist working as a government contractor kills 12 people at the Washington Navy Yard. He is shot dead by police
July 20, 2012 - A masked gunman kills 12 people and wounds 70 when he opens fire at a midnight premiere of Batman film The Dark Knight Rises in Aurora, Denver. He receives a life sentence
October 2002 - Two men ambush 13 people, killing 10 of them, in sniper-style shootings that terrorise the Washington area for three weeks. One sniper was executed and the other was sentenced to life in prison
October 1, 2015 - A man opens fire on the Umpqua Community College campus in southwest Oregon, killing nine people before he is shot dead by police
June 17, 2015 - A white supremacist kills nine black churchgoers at a historic, predominantly black church in Charleston, South Carolina
May 17, 2015 - Rival motorcycle gangs kill nine at a restaurant in Waco, Texas. More than 170 people are arrested
August 5, 2012 - A white supremacist kills six worshippers in a Sikh temple in Oak Creek, Wisconsin. The gunman kills himself
January 8, 2011 - Then-US representative Gabrielle Giffords is the target of an assassination attempt by a gunman in Tucson, Arizona. Six people are killed and 13, including Giffords, are wounded
October 2, 2006 - A gunman kills five girls in a one-room Amish schoolhouse in Nickel Mines, Pennsylvania, before killing himself.