The U.S. had more mass shooting deaths in the first weekend of June than in the previous three-day weekend, which ended with Memorial Day.
The tally for weekend violence through Sunday night was at least 12 killed and at least 38 injured in mass shootings, defined by the Gun Violence Archive as incidents in which “four or more people are shot or killed, not including the shooter.”
During the holiday weekend, nine people were killed and more than 60 others were injured in attacks fitting that definition.
As Americans debate the possibility of new gun regulations in the wake of the horrific school attack in Uvalde, Texas, gun violence seemed to continue unabated, with the official start of summer, June 21, and its hottest nights still ahead.
The most notable violence over the weekend took place in Philadelphia, where three people were killed and 12 others were injured, and in Chattanooga, Tennessee, which had its second weekend in a row of mass-shooter violence, this time with two people dead and 12 others injured by gunfire. A third person died after having been struck by a car.
Other attacks included:
In Clarendon County, South Carolina, a graduation party outside a residence late Saturday was interrupted by a drive-up shooting that may have involved two vehicles, the sheriff's office said.
A 32-year-old woman struck by gunfire died Sunday morning, it said. Seven other people, including children ages 12 to 17 and a 36-year-old, were injured, the office said.
The violence might have been gang-related, the Clarendon County Sheriff's Office said in a statement.
"There were at least 60 to 70 rounds fired at this incident," it said. "It is not clear, as of yet, if some of these rounds may have been return fire from some of the subjects at the party."
In Saginaw, Michigan, early Sunday, a shooting killed three people: two men at the scene and a woman who was hospitalized but did not survive, NBC affiliate WEYI of Saginaw reported.
Two men injured in the attack were hospitalized, the station said.
In Mesa, Arizona, early Sunday, two people were killed and two others were injured in a shooting at a nightclub, NBC affiliate KPNX of Phoenix reported.
Three people who were alleged to have sped away in a vehicle were chased by officers and ultimately stopped and arrested in connection with the attack, the station said.
Two men were pronounced dead at the scene. The injured, also at the venue, were hospitalized with non-life-threatening injuries, authorities told KPNX.
In Bibb County, Georgia, on Saturday night, sheriff's deputies responded to reports of shots fired at an abandoned home and found four people down, including Cleveland Raines, 19, of Macon, who died at a hospital, the county sheriff's office said.
Three other victims, named as Ralph Hughes, 19, Jarvis Devon Hill, 23, and Alizya Sinclair, 22, were said to be stable at medical facilities, the Bibb County office said in a statement.
Origins of the attack were under investigation.
In Phoenix early Saturday, a 14-year-old girl was killed and eight other people were injured when an argument among multiple parties escalated with shots fired at a party.
About 100 people were at the party in a strip mall building in the area of 10th Avenue and Hatcher Road, Phoenix police said.
The shooting took place inside the building, in the nearby parking lot and in the roadway area, police said in a news release. Officers found attendees fleeing in different directions from the parking lot and multiple victims at the scene and nearby.
The 14-year-old girl was pronounced dead after she was taken to a local hospital. Two women sustained life-threatening gunshot wounds, five men sustained non-life-threatening gunshot wounds, and a teenage boy suffered a non-life-threatening gunshot wound.
Shannon Watts, the founder of the group Moms Demand Action, which seeks to curb gun violence, noted on Twitter that the violence is not abating.
"Last month it was New York, Texas and California," she said. "This weekend it’s Pennsylvania, South Carolina and Tennessee."
In an address to the nation Thursday, President Joe Biden called on Congress to act on proposals to curb sales of semi-automatic rifles like the AR-15, which was developed for the military.
Although the weapon has been used in some of the nation's worst mass shootings, authorities in the weekend's attacks did not single out that style of weapon as a culprit.
Biden spoke after 19 children and two teachers were fatally shot at an elementary school in Uvalde on May 24. On May 14, a man alleged to have been motivated by racism and hatred is accused of killing 10 people at a grocery store in the heart of the Black community in Buffalo, New York.
A number of nonprofit groups committed to reducing shootings recognized Friday as National Gun Violence Awareness Day.