First reports came in at about 1 a.m. of the shooting that took place outside the Ned Peppers Bar in Dayton city's Oregon area, according to the BBC.
"We had officers in the immediate vicinity when this shooting began and were able to respond and put an end to it quickly," the BBC quoted the Dayton Police Department wrote in a tweet.
A note saying staff members were safe appeared on Ned Peppers Instagram page after the incident and on the nearby Hole in the Wall bar's Facebook page.
Footage posted on social media showed people running as dozens of gunshots echoed through the streets. It also showed several bodies on the floor covered in white sheets.
A witness told the BBC that he was at a nearby rap performance when they were told to evacuate.
"I was very shocked," he said. "We all evacuated quickly and safely. We were told to avoid the Oregon district."
"I got to my car, I could see cops, multiple ambulances. When I drove past I saw a lot of cops and ambulances."
Sunday night's incident came hours after the mass shooting at a Walmart store near the Cielo Vista Mall in the city of El Paso on Saturday which also left over 25 people injured.
A 21-year-old suspect is currently in police custody. El Paso Police have said that the shooting could be dubbed as possible hate crime and the eighth deadliest in modern US history.
The two attacks came less than a week after a teenage gunman killed three people at a California food festival.
( With inputs from IANS )