NEW YORK, June 12 (Xinhua) -- Fifty people were killed and 53 others wounded early Sunday in a shooting spree at a gay nightclub in Orlando, Florida, which became the worst mass shooting incident in the U.S. history.

The following are the major shooting incidents in the United States that caused deadly casualties in the past decades.

On June 12, 2016, a gunman killed at least 50 people and injured 53 at the Pulse nightclub in Orlando, Florida.

On April 16, 2007, a 23-year-old student from the Republic of Korea went on a shooting spree at Virginia Tech University in Blacksburg of Virginia, killing 32 people and wounding 15 others before killing himself. It was the worst school shooting in the U.S. history.

On Dec. 14, 2012, 20-year-old Adam Lanza killed 28 people including 20 children and eight adults in Sandy Hook Elementary School in the U.S. state of Connecticut. Lanza first killed his mother at their shared home before taking her guns and driving to the school. The incident was the second-deadliest school shooting by a single person in U.S. history, after the 2007 Virginia Tech University shootings.

On Oct. 16, 1991, a 35-year-old gunman crashed his truck through the wall of a Cafeteria in Kileen, Texas, and shot dead 23 people and wounded 27 others. He then committed suicide.

On July 18, 1984, a 41-year-old gunman killed 21 adults and children at a local McDonalds in San Ysidro, California before he was killed by a SWAT team sniper.

On Aug. 1, 1966, a former U.S. Marine killed 14 and wounded at least 30 while shooting from a University of Texas tower in Austin, Texas. Police officers shot the gunman dead in the tower. Before he went on the shooting, he murdered his wife and his mother in their homes.

On Dec. 2, 2015, a married couple shot 14 people dead and wounded 17 in a conference hall at a service center for disabled people where county employees gathered for a celebration in San Bernardino, California.

On Aug. 20, 1986, a part-time mail carrier armed with three handguns killed 14 postal workers in Edmond, Oklahoma in 10 minutes before killing himself.

On Nov. 5, 2009, Maj. Nidal Malik Hasan killed 13 people and injured 32 at Fort Hood, Texas in a shooting rampage. He was convicted and sentenced to death.

On April 3, 2009, Jiverly Wong killed 13 people and injured four during a shooting at an immigrant community center in Binghamton, New York, and then took his own life.

On April 20, 1999, two teenagers killed 12 fellow students and a teacher before committing suicide in the school library in Columbine High School in Littleton, Colorado.

On Feb. 18, 1983, three men entered the Wah Mee gambling and social club in Seattle, Washington, robbed the 14 occupants and shot 13 of them dead.

On Sept. 25, 1982, a prison guard killed 13 people including five of his own children in Wilkes-Barre, Pennsylvania.

On Sept. 5, 1949, a 28-year-old veteran of World War II, shot dead 13 people in Camden, New Jersey. He was found insane and was committed to a state mental institution.

On Sept. 16, 2013, 34-year-old Aaron Alexis fired inside the Washington Navy Yard, killing 12. He was also killed in the shooting.

On July 20, 2012, a heavily-armed 24-year-old gunman killed 12 people and 58 wounded in a shooting at a movie theater in Aurora, Colorado.

On July 29, 1999, a 44-year-old man killed his wife and two children at his home, and then shot dead nine people and injured 12 in two different brokerage houses in Atlanta, Georgia.

On March 10, 2009, Michael McLendon of Kinston in Alabama killed 10 people including his mother, grandparents, aunt and uncle, and then committed suicide.

An average of about 33,000 people were killed by guns each year in the U.S. in the past five years, according to the data released by the U.S. Center of Disease Control.

Reports said that during Obama's seven and half years in office, he has come out to address a major shooting tragedy for a total of 15 times.

So far gun violence has not been a major political issue during this election season. It remains unknown if the latest shooting will ignite heated debate on gun control among the presidential candidates.