Four people were killed and ten others injured when gunfire erupted at a child’s birthday party in Stockton, California, 24NewsHD TV channel reported on Sunday.
According to US media reports, the shooting occurred near an ice cream parlour where families had gathered for the celebration.
Police said an investigation was underway but did not immediately comment on a motive or whether a suspect had been identified.
Authorities cordoned off the area as emergency responders treated victims and transported the injured to nearby hospitals.
Stockton’s deputy mayor confirmed that the attack took place during a birthday gathering, calling the incident “a horrific act of violence targeting a family event.”
Community leaders voiced concern over rising gun-related incidents in the state, urging swift action to ensure public safety.
AFP reported on Sunday that four people were killed and 10 wounded in a shooting in California on Saturday night, US police said, calling it a "targeted incident."
"Approximately 14 individuals were struck by gunfire, and four victims have been confirmed deceased," San Joaquin County Sheriff's office said on social media, adding that information about the shooting in Stockton was limited.
The sheriff's office said detectives were "working to determine the circumstances leading up to this tragedy."
"Early indications suggest this may be a targeted incident, and investigators are exploring all possibilities," it said.
"We are urging anyone with information, video footage, or who may have witnessed any part of this incident to contact the San Joaquin County Sheriff's Office immediately," police said.
California Governor Gavin Newsom had been briefed on the shooting, his office said in a post to social media.