Four children were injured in the shooting at a festival in Independence, Missouri, on Sunday night, US media reported.
The four victims have been taken to the hospital with a threatening non-life injury, said local announcer affiliated by NBC KSHB.
The suspect has escaped from the scene, he said.
The incident occurred at the Santacaligon Days Festival, who celebrated the role of independence as a starting point for the settlers’ cartrid train that headed west in the 19th century.
Police officials and festivals did not immediately respond to a comment request.
The festival was set to hit Labor Day weekend, it was closed on Friday night due to bad weather.
It usually attracts around 300,000 visitors every year.