The Los Angeles County Sheriff's Department said the shooting at Star Ballroom Dance Studio in Monterey Park was reported at 10:22 p.m. Saturday.
"Our very preliminary description has been described as a male Asian" between the ages of 30 and 50, Los Angeles County Sheriff Robert Luna said. He said five men and five women were killed.
Monterey Park is a city of 60,000 people about 10 miles east of downtown Los Angeles. The shooting took place shortly after a Lunar New Year celebration brought thousands of people to the city, which has a predominantly Asian population.