The shooter, Omar Mateen of Port St. Lucie, Florida., opened fire with an assault-type rifle and a handgun at the crowded club at about 2 a.m. Sunday. In addition to the 50 people who were killed, an additional 53 were injured, officials said at a press conference.
The death toll makes the attack deadlier than the 2007 Virginia Tech shooting, in which student Seung-Hui Cho shot 32 people to death before killing himself, and the 2012 Sandy Hook Elementary School shooting in Newtown, Conn., in which gunman Adam Lanza killed 27 people before killing himself.
Here is a list of America's deadliest mass shootings.
50 people, June 12, 2016 After a gunman opened fire at a prominent gay club in Orlando early on Sunday morning, 50 people were killed and 53 injured. Police killed the shooter after he held some locals in the club hostage.
32 people, April 17, 2007 A 23-year-old student at Virginia Tech in Blacksburg, Virginia killed 32 people in shooting spree in two locations. The shooter, Seung-Hui Cho pre-recorded a video of him ranting about rich "brats" and complaining about being bullied. Cho killed himself on the scene.
27 people, December 14, 2012 20-year-0ld Adam Lanza gunned down 20 children between the ages of 6 and 7 at Sandy Hook Elementary School in Newtown, Connecticut, as well as six adults and school staff before killing himself. Lanza committed suicide.
23 people, October 16, 1991 George Hennard crashed his pickup truck through the walls of Luby's Cafeteria, a packed restaurant in Killeen, Texas. The 35-year-old then shot and killed 23 people before killing himself. A former roommate said he hated "blacks, Hispanics, gays" and said women were "snakes."
21 people, July 18, 1984 A security guard fired from his job entered a McDonald's in San Ysidro, California with a shotgun and killed 21 employees and customers, including children. The guard, 41-year-old James Huberty, was killed by a police sniper an hour after he started shooting.
18 people, August 1, 1966 A 25-year-old former marine, Charles Joseph Whitman, went to the top of a tower at the University of Texas at Austin shortly after killing his wife and mother, and shot and killed 16 people on the campus , wounding 30. He was then killed by a police officer.
14 people, December 2, 2015 Husband-and-wife couple Syed Rizwan Farook and Tashfeen Malik opened fire at an employee gathering in San Bernardino, California, killing 14 people. Both were radicalized in the United States and discussed jihad in private messages to each other.
14 people, August 20, 1986 A part-time mail carrier in Edmond Oklahoma, Patrick Henry Sherrill, armed with three handguns, kills 14 postal workers 10 minutes before killing himself.
13 people, November 5, 2009 Maj. Nidal Malik Hasan killed 13 people and injured 32 in a shooting at Fort Hood, Texas during a shooting rampage. He was caught and sentenced to death.
13 people, April 20, 1999 Students at Columbine High School in Littleton, Colorado, Eric Harris, 18, and Dylan Klebold, 17, shot and kill 12 other students and a teacher. They committed suicide in the school's library.
13 people, February 18, 1983 Three men robbed 14 people in a gambling club in Seattle, shooting each of them in the head and killing 13. Two of them were were convicted of murder, while the third was convicted of robbery and second-degree assault and deported to Hong Kong in 2014.
13 people, September 25, 1982 40-year-old prison guard and army veteran George Banks killed 13 people in Wilkes-Barr, Pennsylvania, including five of his own children. He was sentenced to death but the ruling was overturned by the Pennsylvania Supreme Court after finding Banks mentally unfit.
13 killed, September 5, 1949 A 28-year-old World War II veteran named Howard Unruh killed 13 people on the street of Camden, New Jersey with a German Luger pistol. He was found insane sent to a mental institution.
12 people, September 16, 2013 James Holmes, a 24-year-old recent neuroscience PhD at the University of Colorado, killed 12 people and wounded 58 in a crowded movie theater in Aurora, Colorado. Holmes is serving life in prison without parole.
12 people, July 29, 1999 44-year-old Mark Barton of Atlanta killed his wife and two children at his Atlanta home, then opened fire in two separate stock brokerage houses, killing nine people and wounding 12.
12 people, September 16, 2013 Aaron Alexis, a 34-year-old former Navy officer shot and killed 12 people at the Washington Navy Yard.