At least four people were killed and ten others injured in a shooting on Saturday night during a family gathering in Stockton, a city in northern California, authorities said.

The shooting occurred around 6 p.m. Pacific Time (0200 GMT on Sunday) and the victims included both juveniles and adults, said Heather Brent, spokesperson for the San Joaquin County Sheriff's Office, at a briefing.

The suspect remained at large and no arrests have been made, Brent said.

"Early indications suggest this may be a targeted incident, and investigators are exploring all possibilities," the office said in a Facebook post.

The "mass shooting" took place at a child's birthday party in an ice cream shop, according to Stockton Vice Mayor Jason Lee.

Authorities have not yet released details about the suspect or a possible motive, and the circumstances leading to the shooting remain unclear. California Governor Gavin Newsom has been briefed on the incident.