Three of the deadliest mass shootings in US modern history have occurred in the last five months.
On Wednesday, a gunman opened fire on a high school in southeastern Florida, killing at least 17 people and injuring more than a dozen others.
In early November 2017, at least 26 people were killed in a mass shooting during a church service in Sutherland Springs, Texas, making it the "largest mass shooting in state history", Governor Greg Abbott said.
The shooting came about a month after Stephen Paddock opened fire on concert-goers at the Mandalay Bay Resort and Casino on the Las Vegas Strip, killing 58 people and injuring more than 500 others.
The three shootings are among the deadliest in the US since 1949.
Here's a look at the deadliest mass shootings in the US over the last two decades:
Mandalay Bay, Las Vegas (2017): At least 58 killed
- Shooter Stephen Paddock opened fire on the crowd of concert-goers at a country music festival at the Mandalay Bay Resort and Casino, killing more than 58 people and injuring 500 others.
Pulse nightclub (2016): 49 killed
- A heavily armed gunman killed 49 people inside a gay nightclub in the city of Orlando on June 12, 2016.
- The attacker, US citizen Omar Mateen, was killed in a gun battle with police. He had pledged allegiance to the Islamic State of Iraq and the Levant (ISIL) group, which later claimed responsibility for the attack.
Virginia Tech (2007): 32 killed
- A 23-year-old student, South Korean national Seung-Hui Cho, went on a rampage at Virginia Tech University in April 2007, killing 27 students and five teachers before committing suicide.
Sutherland Springs, Texas church: At least 26 killed
- A gunman opened fire on a Sunday morning church service in the small rural town of Sutherland Springs, Texas, killing at least 26 people and injuring 20 others. The youngest person killed was five years old.
Sandy Hook (2012): 26 killed
- A 20-year-old American citizen, Adam Lanza, killed his mother in December 2012 before shooting and killing 20 children and six adults at Sandy Hook Elementary School in Newtown, Connecticut. He later committed suicide.
Texas restaurant (1991): 22 killed
- In October 1991, 35-year-old George Hennard, a US citizen, shot dead 22 people in a restaurant in the town of Killeen before shooting himself.
Florida high school (2018): At least 17 killed
- A former student opened fire on Marjory Stoneman Douglas High School in southeastern Florida, killing at least 17 and injuring more than a dozen others.
San Bernardino (2015): 14 killed
- A newlywed couple - US citizen Rizwan Farook and his Pakistani wife Tashfeen Malik, who was a permanent resident - stormed an office party at a social services centre in San Bernardino, California in December 2015, killing 14 people and injuring 22 others. The couple was shot dead by police.
Fort Hood military base (2009): 13 killed
In November 2009, US Army psychiatrist Nidal Hasan opened fire at his military base in Killeen, killing 13 people and injuring 42 others.
New York immigrant centre: 13 killed
- A Vietnamese immigrant, Jiverly Antares Wong, shot and killed 13 people at a civic centre in the city of Binghamton in April 2009, before killing himself.
Navy Yard headquarters (2013): 12 killed
- Former serviceman Aaron Alexis, a US citizen, shot randomly at workers at the Washington Navy Yard headquarters in September 2013, killing 12 people before he was shot dead by police.
Aurora, Colorado (2012): 12 killed
- James Holmes, a US citizen born in California, wearing body armour stormed a cinema showing a late-night premiere of a Batman film in Aurora, Colorado in July 2012, opening fire and releasing tear gas. Twelve people were killed and 70 others wounded. Holmes was sentenced to life in prison.
Columbine High (1999): 13 killed
- Two American teenage boys - Eric Harris and Dylan Klebold - shot and killed 12 classmates and a teacher, before killing themselves at Columbine High School in Littleton, Colorado, in April 1999.
Source: Al Jazeera and news agencies