At least four people, including three children, have been killed in a mass shooting at a family gathering in California, authorities say.

The victims were aged 8, 9, 14, and 21, according to a spokesperson for the San Joaquin County Sheriff's Office. Eleven others were injured in the incident at a restaurant in Stockton.

A suspect is still at large, and police believe the shooting may have been targeted.

Deputy Mayor Jason Lee noted that the shooting occurred at a children's birthday party, although police have yet to confirm specific details about the event aside from it being a family gathering.

[A] birthday party should never be a place where families fear for their lives, Deputy Mayor Lee expressed on social media.

The shooting transpired shortly before 6 PM local time (02:00 GMT on Sunday), and the Sheriff's Office is requesting that anyone with information or video footage come forward.

Spokeswoman Heather Brent described the situation as unfathomable, adding that investigators are exploring all possibilities related to the case.

Stockton's Mayor Christina Fugazi condemned the shooting as unacceptable, emphasizing that families should be together instead of standing by their loved ones in hospitals.

California has some of the strictest firearm laws in the U.S. but continues to face challenges regarding gun control. In recent years, a federal judge overturned the state's ban on assault weapons, and the U.S. Supreme Court expanded gun rights, jeopardizing similar regulations in California.