Police are attending a shooting in Monterey Park in California following reports of multiple casualties, the Los Angeles Times says, citing a law enforcement source on Saturday night (local time).

The shooting took place after 10pm (4pm AEST) around the location of a Chinese Lunar New Year celebration held in Monterey Park, the newspaper reported.

Tens of thousands of people had attended the festival earlier in the day.

Footage posted on social media showed deserted, cordoned-off streets guarded by police cars.

Monterey Park is a city in Los Angeles county, around 11km from downtown Los Angeles.

More to come.