The massacre of 12 people in Virginia by a “disgruntled” worker is the 568th known American mass shooting in the past two years.

At least 802 people have died in shootings involving four or more people in this period, data collected by the Gun Violence Archive shows.

The city’s mayor described the Virginia Beach atrocity as the most devastating day in the history of the city.

Despite widespread protests, calls for tighter gun laws and major controversies within the National Rifle Association, politicians face an uphill battle to introduce new rules.

However, the issue of gun legislation looks set to become a major one for candidates in the 2020 election, with presidential hopeful John Hickenlooper already endorsing tighter laws.

Here The Independent looks at some of the the deadliest mass shootings in the United States over the past two years.

Mass shootings in America Show all 8 1 /8 Mass shootings in America Mass shootings in America Camden shootings – 1949 Howard Unruh killed 13 people, including three children, during a 12-minute walk through his neighborhood on September 6, 1949, in Camden, New Jersey, when he was 28 years old. The incident became known as the "Walk of Death". Unruh was found to be criminally insane and died in 2009 after a lengthy illness at the age of 88, following 60 years of confinement. Alamy Mass shootings in America University of Texas tower shooting – 1966 Charles Whitman killed 17 people and injured 31 others in Austin, Texas. After stabbing his mother and wife the night before, he headed to the University of Texas, where he opened fire on people in the campus and streets from the observation desk. He was shot dead after a policeman and civilian reached the scene. Austin History Center, Austin Public Library Mass shootings in America Easter Sunday Massacre – 1975 James Ruppert killd 11 family members in his mother's house, which included his mother, brother and his wife, as well as their eight children. He used a magnum, two handguns and a rifle. Mass shootings in America Wilkes-Barre shootings – 1982 Former prison guard, George Banks, shot dead 13 people in Pennsylvania, including five of his own children. AP Photo/Times Leader Mass shootings in America Wah Mee massacre – 1983 Three men, Kwan Fai Mak, Wai-Chiu Ng, and Benjamin Ng, killed 13 people who were in Seattle's Wah Mee gambling club. YouTube/KIRO 7 News Mass shootings in America San Ysidro McDonald's massacre – 1984 James Huberty killed 21 people and injured 19 others after he walked in a McDonald's in San Diego. He was shot dead by a sniper after 78 minutes of him entering the restaurant. Alamy Mass shootings in America Palm Sunday massacre – 1984 Ten people were shot dead from handguns at close range in a New York home. A baby girl was the only survivor after convicted dealer, Christopher Thomas, shot three women, one teenage girl and six children in their Brooklyn home. Thomas was convicted of manslaughter and cleared of murder. He was released from prison after 32 years. Mass shootings in America Edmond post office shooting – 1986 Patrick Sherrill, a postal worker at the Edmond post office in Oklahoma, killed 14 co-workers and injured 6 others, before he shot himself. Oklahoma Highway Patrol Collection

— 15 Feb 2019: Gary Martin killed five co-workers at a manufacturing plant in Aurora, Illinois, during a disciplinary meeting where he was fired. He wounded one other employee and five of the first police officers to arrive at the suburban Chicago plant before he was killed in a shootout with police.

— 7 Nov 2018: Ian David Long killed 12 people at a country music bar in Thousand Oaks, California, before taking his own life. Long was a Marine combat veteran of the war in Afghanistan.

— 27 Oct 2018: Robert Bowers is accused of opening fire at the Tree of Life synagogue in Pittsburgh, Pennsylvania, during Shabbat morning services, killing 11 people and injuring several others. It’s the deadliest attack on Jews in US history.

— 28 June 2018: Jarrod Ramos shot through the windows of the Capital Gazette offices in Annapolis, Maryland, before turning the weapon on employees there, killing five at the Capital newspaper. Authorities say Ramos had sent threatening letters to the newspaper prior to the attack.

— 18 May 2018: Dimitrios Pagourtzis began shooting during an art class at Santa Fe High School in Texas. The 17-year-old killed eight students and two teachers and 13 others were wounded. Explosive were found at the school and off campus.

— 14 Feb 2018: Nikolas Cruz shot and killed 17 students and staff members at Marjory Stoneman Douglas High School in Parkland, Florida. It surpassed Columbine High School as the deadliest shooting at a high school in US history.

— 5 Nov 2017: Devin Patrick Kelley, who had been discharged from the US Air Force after a conviction for domestic violence, used an AR-style firearm to shoot up a congregation at a small church in Sutherland Springs, Texas, killing more than two dozen people.