The murder of 26 people, including 20 children, at an elementary school in Newtown, Connecticut is one of the deadliest shootings in US history.
The massacre took place less than six years since the worst school shooting in US history: the 2007 Virginia Tech massacre.
ITV News' Juliet Bremner reports on the debate over gun ownership in the US:
On April 16, 2007, student Seung Hui Choi, killed 32 people and wounded 17 others before killing himself on the Virginia Tech.
The victims of Virgina Tech were in the late teens and early twenties, in comparison to the Connecticut massacre: the majority of the victims range between five and 10-years-old.
Before Virginia Tech, the most deadly massacre was the Columbine High School shooting. On April 20, 1999 18-year-old Eric Harris and Dylan Klebold opened fire in Littleton, Colorado, killing 12 classmates and a policeman before committing suicide.
Shocking as Columbine, Virginia Tech and now the Connecticut massacre may be, the trend of shooting sprees in the United States stretches back decades:
- 1966: 16 people were killed and more than 30 were wounded during a 96-minute rifle rampage by student Charles Whitman at the University of Texas in Austin.
- 1976: Seven people were killed in the library of California State University, Fullerton
- 1984: 21 people were killed in an MacDonalds in San Ysidro, California by an out-of work security guard called James Oliver Huberty.
- 1986: 14 people people were shot by Pat Sherrill inside a post office in Edmond, Oklahoma.
- 1991: 23 people were killed after George Hennard opened fire at a Cafe in Killen, Texas.
- 2009: Thirteen soldiers and civilians are killed and more than two dozen wounded when a gunman walks into the Soldier Readiness Processing Centre at Fort Hood, Texas, and opens fire.Army psychiatrist Major Nidal Hasan is charged with 13 counts of premeditated murder and 32 counts of attempted premeditated murder.
- August 5, 2012: At least 12 people are killed when a gunman enters a cinema in Aurora, Colorado, releases a canister of gas and then opens fire during the opening night of the Batman movie The Dark Knight Rises
- July 20, 2012: Army veteran Wade Michael Page kills five men and one woman and wounds three other people, including a police officer, before taking his own life at the Sikh Temple of Wisconsin outside Milwaukee.