At least six people died and at least nine were injured in an early-morning shooting in Sacramento, California, the city's police department said on Twitter.
Police said several blocks of a commercial stretch of the downtown area were closed while they investigate. Videos posted online showed people shouting and running in the street.
Reuters could not independently verify the footage.
The incident comes a little more than a month after a man shot and killed his three children and a fourth person before taking his own life in the same city.
Israeli strikes kill 26 in Gaza, health officials say
US government starts likely brief shutdown as House fails to approve deal
Thousands demonstrate in Minnesota and across US to protest ICE
France tightens infant milk rules after recalls
