Louisville police tweeted that the "suspected shooter has been neutralized," adding, "There is no longer an active aggressor threat."

Louisville Mayor Craig Greenberg tweeted that residents should avoid the area around Slugger Field until further notice.

Kentucky Gov. Andy Beshear said he is heading to the scene.

"Please pray for all of the families impacted and for the city of Louisville," he tweeted.

FBI and ATF agents are assisting with the incident.

Officers arrived at the Old National Bank within three minutes of being dispatched and found the suspect still firing, Louisville police said.

Officers exchanged gunfire with the suspect who died at the scene, police said. It's not yet clear if the suspect's wounds were self-inflicted, police said.

Four victims were killed and eight people are injured, police said.

At least two officers were shot during the exchange of gunfire, police said, including one who is undergoing surgery.

It appears the suspect was a previous or current employee, police said.

"This is awful. I have a very close friend that didn't make it today. And I have another close friend who didn't, either, and one who is at the hospital that I hope is gonna make it through," Kentucky Gov. Andy Beshear said at a news conference.

"The safety of Old National Bank employees and everyone we serve in our banking center locations is paramount,” Jim Ryan, the CEO of Old National Bank, said in a statement. “As we await more details, we are deploying employee assistance support and keeping everyone affected by this tragedy in our thoughts and prayers."