At least four people have been killed in a mass shooting at a child's birthday party in California.

Ten others were injured in the shooting at a restaurant on Saturday evening, in the state's northern city of Stockton.

A suspect is still on the loose and police say they believe the shooting may have been "targeted".

Local police say the victims include adults and children. The conditions of the injured have not been confirmed.

The San Joaquin county sheriff's office said the shooting happened shortly before 18:00 local time, while spokesperson Heather Brent described the incident as "unfathomable".