Four men have been killed and six injured in what police believe was a targeted shooting at a family gathering in California.

Police say about 40 people had gathered to watch football in the backyard of a home in Fresno on Sunday, when at least one gunman came in and opened fire.

“It’s very likely that it was targeted, we just don’t know why,” Fresno police chief Michael Reid told reporters.

The attack occurred just days after a school shooting in southern California.

No suspects have been identified so far.

Police described the victims as Asian men between 25- and 30-years-old. Three were found dead at the scene. The fourth died in hospital.

Five others who were injured are recovering.