According to media reports, numerous people were injured by gunfire at a Chinese New Year celebration in the Los Angeles area.
The AFP news agency quoted the police as saying nine people had died.
According to eyewitnesses, a man shot himself with an automatic rifle.
The incident happened on Saturday evening shortly after 10 p.m. (local time, 7 a.m. CET on Sunday) in Monterey Park, an eastern suburb of the Pacific metropolis in the American state of California.
According to the newspaper report, it was still unclear whether there had been any arrests.
The owner of a restaurant near the crime scene said three people ran into his place and asked him to lock the door.
They said the shooter carried so much ammunition that he could reload over and over again.