Ten people were shot dead during a Chinese New Year celebration in the Los Angeles area.
The crime happened on Saturday evening in Monterey Park, an eastern suburb of the Pacific metropolis in the US state of California, as the Los Angeles County Sheriff's Office announced on Twitter.
According to media reports, numerous people were also injured by gunshots.
According to eyewitnesses, a man shot himself with an automatic rifle.
According to a report by the Los Angeles Times, 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.
The incident happened just after 10 p.m. on Saturday evening (7 a.m. CET on Sunday).
Tens of thousands gathered in Monterey Park to celebrate Chinese New Year.
At one of the largest events of this kind in the region, there was not only dancing, there were also numerous food and shopping stalls.
Approximately 61,000 people live in Monterey Park, most of whom are Americans with an Asian immigrant background.