Monday's mass shooting at a supermarket in Boulder, Colorado, comes less than a week after eight people were killed in a series of attacks on spas in Atlanta.
The two incidents are likely to spur discussion about gun control legislation in the United States, where firearm deaths are tragically common. They are also among at least seven mass shootings in the past week across the US -- including three incidents on Saturday alone.
Atlanta, March 16: Eight people, including six Asian women, were killed when a White gunman stormed three spas, police said.
Stockton, California, March 17: Five people who were preparing a vigil in Stockton, in California's Central Valley, were shot in a drive-by shooting, the San Joaquin Sheriff's Department said. None had life-threatening injuries.
Gresham, Oregon, March 18: Four victims were taken to the hospital after a shooting in the city east of Portland, police said in an initial report on Twitter.
Houston, March 20: Five people were shot after a disturbance inside a club, according to police. One was in critical condition after being shot in the neck, the rest were in stable condition, according to CNN affiliate KPRC.
Dallas, March 20: Eight people were shot by an unknown assailant, one of whom died, according to police.
Philadelphia, March 20: One person was killed and another five were injured during a shooting at an illegal party, CNN affiliate KYW reported. "There were at least 150 people in there that fled and believed they had to flee for their lives,” Philadelphia Police Commissioner Danielle Outlaw said.
Boulder, Colorado, March 22: Ten people, including a Boulder police officer, were killed in a shooting at the King Soopers supermarket, according to police.
It's unclear how this number of mass shootings -- in which at least four people were shot -- compares to an average week in the US.
Though some official gun violence data is available, the US federal government does not have a centralized system or database to track firearm incidents and mass shootings nationwide. According to the Centers for Disease Control and Prevention, which tracks some gun violence data, nearly 40,000 people were killed in incidents involving firearms in 2019.
So far this year, there have been at least six mass shootings with four or more killed, including those in Atlanta and Boulder.
These are the other four: