The shooting at a gay nightclub in Orlando, Florida, where 50 people have been killed, is part of a tragic list in modern US history.
Fifty people are confirmed dead and another 53 people are wounded after a 29-year-old gunman opened fire inside a gay nightclub.
The suspect has been named as Omar Mateen, of Port St. Lucie, Florida. Authorities are investigating the shooting as an act of terrorism.
The attack is the deadliest mass shooting in modern US history.
San Bernardino, California, 2 December, 2015
At least 14 people were killed and more than a dozen injured after two gunmen open fire at a social services centre.
Police said a male suspect and a female suspect were later killed in a shoot out with officers.
Umpqua Community College, Roseburg, Oregon, 1 October, 2015
Ten people were killed and seven wounded in a shooting at the college.
Gunman Christopher Harper-Mercer, 26, exchanged fire with police before killing himself.
Charleston, 17 June, 2015
Nine black worshippers - six women and three men - were killed by a gunman during a prayer service at a church in Charleston, South Carolina.
Isla Vista, California, 23 May, 2014
Elliot Rodger, 22, killed six people and injured 14 others near the campus of University of California, Santa Barbara.
Rodger first stabbed three men to death in his apartment and then drove to a sorority house and shot three female students outside, killing two.
He then drove to a deli and shot dead a male student before he took his own life.
Washington Navy Yard, 16 September, 2013
Twelve people were killed in a mass shooting inside the Washington Navy Yard by lone gunman Aaron Alexis, who was later killed by police.
It was the second worst attack on a US military base after the Fort Hood shooting in November 2009.
Hialeah, Florida, 26 July, 2013
Pedro Vargas, 42, went on a shooting rampage at his apartment building, killing six people before he was shot dead by police.
Sandy Hook, Connecticut, 14 December, 2012
Adam Lanza, 20, killed his mother before opening fire at Sandy Hook Elementary School in Newtown, Connecticut, killing 20 children and six adults.
He then turned the gun on himself. It was the worst school shooting in America's history.
Minneapolis, 27 September, 2012
Andrew Engeldinger, who had just been fired from his job at Accent Signage Systems, pulled a gun and fatally shot six people, including the company founder, in Minnesota's deadliest workplace killing spree.
He also wounded two others before killing himself.
Oak Creek, Wisconsin, 5 August, 2012
Wade Michael Page, 40, killed six worshippers at a Sikh Temple before taking his own life.
Aurora, Colorado, 20 July, 2012
A masked gunman burst into a cinema during a midnight showing of the Batman movie The Dark Knight Rises, throwing tear gas before opening fire.
James Holmes, then 24, was convicted of killing 12 people and injuring more than 70. A jury rejected the death penalty for his shooting rampage.
Oikos University, Oakland, California, 2 April, 2012
Seven people were killed and three more wounded when a former student of the university began shooting.
One Goh, 43, was charged with seven counts of murder and three counts of attempted murder, but psychiatric evaluations concluded he suffers from long-term paranoid schizophrenia and is unfit to stand trial.
Fort Hood, Killeen, Texas, 5 November, 2009
A 42-year-old US Army Major, serving as a psychiatrist, opened fire inside the US military base killing 13 and wounding 29 in an attack deemed an act of terrorism.
Nidal Hasan was shot and captured and is paralysed from the waist down.
Before the killing he had been in touch with the late al Qaeda recruiter Anwar al Awlaki to ask whether he would be considered a martyr if he died shooting US soldiers.
Virginia Tech, Blacksburg, Virginia, 16 April, 2007
Seung-Hui Cho, 23, killed 32 and injured 17 in what was then America's deadliest shooting.
He launched two separate attacks at the campus two hours apart before killing himself. Cho had a history of mental illness and was in therapy through his school years.
Nickel Mines, Pennsylvania, 2 October, 2006
Charles Carl Roberts shot dead five and injured five in an attack at an Amish school. The 32-year-old dish washer at a local restaurant then killed himself.
He was driven by anger at God over the death of his premature daughter.
Red Lake Indian Reservation, 21 March, 2005
Sixteen-year-old Jeffrey Weise killed his grandfather and grandfather's companion before opening fire at Red Lake High School.
He killed nine and injured seven, then took his own life. He blamed years of school bullying for the attack.
Forth Worth, 25 September, 1999
Unemployed white supremacist Larry Gene Ashbrook opened fire on the congregation of Wedgwood Baptist Church, killing seven and wounding seven.
He then turned the gun on himself. Ashbrook, 47, was a member of a group that advocated killing minorities.
Atlanta, 29 July, 1999
Mark Orrin Barton, a trader, opened fire in two investment offices killing nine and wounding 12. He killed himself after a six-hour police manhunt.
The 44-year-old had been upset by big financial losses.
Columbine High School, Colorado, 20 April, 1999
Students Eric Harris, 18, and Dylan Klebold, 17, opened fire on schoolmates after bombs they had planted in the cafeteria failed to go off.
They killed 13 and injured 21 before killing themselves.
The students were motivated by their anger at society. Harris had a history of depression.
McDonald's, San Ysidro, California, 18 July, 1984
Welder James Huberty walked into a McDonald's and opened fire killing 21 people and wounding 19 before being shot by a police sniper.
The 51-year-old thought society was about to collapse. When asked where he was going as he left the house for the killing, he told his wife: "hunting humans".
University of Texas, Austin, 1 August, 1966
Engineering student Charles Joseph Whitman, 25, opened fire on students from the 28th floor of the main campus building.
He killed 13 and wounded 32 before being shot dead by a police marksman. He also killed his wife and mother.
In a note he said he was suffering irrational thoughts and wanted to relieve his wife and mother from suffering but offered no explanation for the university attack.
