The bank building was locked down for most of the morning, and surrounding streets and sidewalks were closed off.
NBC5 reports that Alcohol, Tobacco and Firearms spokesperson Suzanne Dabkowski announced that ATF officials are now at the bank after an armed suspect opened fire in the lobby and loading dock area at the Fifth Third Bank at 511 Walnut Street.
The chief says they had a "quick response" and 'there is no additional threat'.
To recap, just after 9, emergency responders went to 5/3rd Bank at 5th and Main for report of active shooter with multiple victims.
Police in the United States city of Cincinnati say they've responded to an active shooter situation at a building downtown.
A woman named Ibony Ginyard, who was working in a Dunkin' Donuts in the building's lobby at the time of the attack, said she and the other employees ducked behind the counter as they heard at least five or six gunshots.
Londberg quoted the witness as saying, "I saw a guy in a white shirt walking around and shooting like this" (the witness held up his right arm straight in front of him) 'bing bing bing bing, '" and then added, "He ran.
Police identified him as Omar Enrique Santa Perez, 29, but said they don't know what motivated the attack. "Police responding to 5th/3rd bank building for possible shooting", the station reported on Twitter.
In a press conference, authorities called it a "horrific situation". "We are in the very early stages and are beginning an investigative process".
Federal agents were on the scene as police searched through the building.
Three people died of their wounds and two others remained hospitalized. One has been upgraded to serious condigtion and the other is in fair condition, according to UC Health. At least four people have been taken to hospital.
Cincinnati Mayor John Cranley credited police and firefighters for their heroic actions, running into the bank lobby to confront the shooter.
The Fountain Square often hosts concerts, dancing, food trucks and other events around lunchtime or in the evenings and is neighbored by a hotel, restaurants and retail shops.
A spokeswoman for the University of Cincinnati Medical Center said three men and one woman were treated there for gunshot wounds.
"It's heartbreaking", Cranley said.
Witnesses described the terrifying scene. Leonard Cain was going back inside the bank when someone alerted him to the shooting. Although people tried to get her attention before she entered the building, she was wearing headphones and did not hear them. It is the principal subsidiary of Fifth Third Bancorp, a bank holding company.