The deadly shooting at the highly secured Washington Navy Yard that killed 13 people including the gunman on Monday was the latest in a series of shooting crime in the United States.
Below are some of the worst such firing incidents in recent years.
May 13, 2013: Nineteen people including two young children are injured when gunfire erupted at a Mother's Day parade in New Orleans, police said. Ten men and seven woman are shot along with a 10-year-old girl and 10-year-old boy.
March 22: A Marine kills a male and female colleague in a shooting incident linked to a 'love triangle' at Marine Corps Base in northern Virginia before killing himself.
February 11: Four people are wounded outside a Bourbon Street nightclub in the French Quarter during a shooting as crowds gathered for the city's annual Mardi Gras celebrations.
January 05: Four people, including an armed suspect, die after an hours-long police standoff at a Colorado town home. The victims are believed to be related to the gunman.
December 14, 2012: A heavily armed gunman kills at least 20 children and six adults at an elementary school in Newtown, Connecticut, and a body is found elsewhere in the town. The gunman is also dead.
December 11: A gunman opens fire inside an Oregon shopping mall, killing two people and wounding one. He then kills himself.
August 5, 2012: A gunman kills six people during Sunday services at a Sikh temple in Oak Creek, Wisconsin, before he is shot dead by police.
July 20: A masked gunman kills 12 people and wounds 58 when he opens fire on moviegoers at a showing of the Batman film "The Dark Knight Rises" in Aurora, a suburb of Denver. A 24-year-old former university student is charged in connection with the