The suspect had walked into the Walmart in Beavercreek, Ohio, a town of about 46,000 in the Dayton metropolitan area, around 8:30 p.m. and began firing a gun, according to the Beavercreek Police Department. Four people were wounded and transported to area hospitals.

"The conditions of the victims right now is unknown," Beavercreek Police Capt. Scott Molnar said at a news conference late Monday.

The shooter died from an apparent self-inflicted gunshot wound, police said. The suspect's name, a motive for the attack, and other details weren't immediately released.

Police added that no shots were fired by responding officers. Earlier on social media, police said the store had been cleared and secured and there wasn't any "active threat."

The Bureau of Alcohol, Tobacco, and Firearms, the Ohio Bureau of Criminal Investigation, the FBI, and other local agencies are assisting Beavercreek police with the investigation.

"We're heartbroken by what's happened at our Beavercreek, Ohio store. This remains a developing situation, and we're working closely with investigators on the scene," Walmart said in a statement, WHIO-TV reported.

Part of Dayton's metropolitan area and located just east of the city, Beavercreek has a population of around 46,000 people.