Cincinnati police at the scene of the Cameo Night Club shooting
Local media said the the shooting took place at the Cameo Night Club.
Cincinnati Police Sergeant Eric Franz told CNN several people are undergoing surgery after the gun attack.
He said police did not have any suspects in custody but were interviewing witnesses.
Sgt Franz said he believed "multiple shooters" were involved.
He said the motive was still unclear but added there was no reason to suspect terrorism.
He said the nightclub hires police officers for extra security.
Two officers were stationed at the club's entrance and another two in the car park.
Assistant Police Chief Paul Neudigate said several victims had suffered life-threatening injuries.
He said: ”We are in the middle of a very horrific situation that occurred at the nightclub with multiple victims.
“It's going to be a long night for our homicide units to investigate."
He described it as a "chaotic crime scene" and said police were looking for witnesses, many of whom scattered when the shooting started.
He said:” ”Many of the witnesses fled, but everyone that we can identify is being interviewed.”
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