The FBI defines an active shooter as either one or more individuals who "actively engaged in killing or attempting to kill people in a populated area." However, a mass shooting is defined as when "three or more killings" take place in a single event.
There were 61 active shooter incidents in the United States in which 103 people were killed and 140 others injured, excluding the shooters, the release said. Of the 61 incidents, 12 met the criteria for a mass shooting.
"For the period 2017-2021, active shooter incident data reveals an upward trend," the FBI said in a press release. "The number of active shooter incidents identified in 2021 represents a 52.5% increase from 2020 and a 96.8% increase from 2017."
Of the analyzed shooting events, six of the incidents took place in California, five in Georgia and Texas, and four in both Colorado and Florida.
The report did not include any gun-related events that were classified as gang violence, self defense, domestic disputes, drug violence, hostage situations, or a criminal act that did not put "other people" in danger.
The FBI report comes on the heels of a string of shootings that took place in the United States since late April.
On May 14, an 18-year-old mentally disturbed gunman killed ten people and injured three others in a supermarket in Buffalo, New York. The FBI qualified the incident as a racially-motivated hate crime. The next day, a gunman opened fire inside a church in Laguna Woods, California, killing one person and wounding five others.