Police have confirmed nine people have been killed in the second mass shooting in the US overnight.
Another 16 people were injured in the incident in Oregon District of Ohio in the early hours of Sunday morning.
Lt Col Matt Carper told a press conference that the suspect was shot dead by responding officers.
He was wearing body armour and was armed with a high-capacity rifle with multiple ammunition magazines.
Dayton police tweeted that an active shooter situation began in the Oregon District at 1.22am local time, but that officers nearby were able to “put an end to it quickly”.
Police believe there was only one gunman and have not yet identified the suspect or a motive.
The Oregon District is a historic neighbourhood near central Dayton that is home to entertainment options including bars, restaurants and cinemas.
The Dayton Daily News said the shooting occurred at or near an establishment called Ned Pepper’s Bar.
The Ohio shooting occurred just hours after at least 20 were murdered in a separate incident in El Paso, Texas.
A suspect in the El Paso shooting has been detained and police are investigating if the 21-year-old deliberately targeted Hispanics in what they describe as a possible “hate crime”.
The latest shooting in Ohio
Videos posted to social media show people running through the streets as a rapid popping noise ― apparently gunfire ― can be heard.
Terrea Little, a spokeswoman at Miami Valley Hospital in Dayton told HuffPost that the hospital was treating 16 victims from the shooting, though she provided no details on their conditions.
A large investigation is now underway and police are appealing for information.
Singer Lizzo has said it was a “close call” for her family in Dayton, Ohio, after a shooting left nine people dead and at least 16 injured.
She wrote on Twitter: “Just got off the phone w/ fam in Dayton… it was a close call for them but that’s not the case for 9 other families between this & the terrorist attack in El Paso & recent other shootings.
“I feel completely helpless.. make noise & bring awareness.. vote.. don’t normalize this.”