(CNN) -- An Independence Day parade in Iowa descended into chaos when when two horses went out of control and took their wagon with them, running into crowds of celebrants and leaving more than 20 people injured, according to authorities.
It happened at the Bellevue Heritage Day Celebration Parade in Bellevue, Iowa, on the state's eastern border with Illinois.
Fire Chief Chris Rowling told CNN that emergency officials responded to a call that came in just before noon, about a "mass casualty incident" at the annual Fourth of July parade.
Rowling said two horses pulling a wagon went out of control along the parade route. They ran with the wagon for about six blocks, hitting numerous children and adults.
A total of 24 people were taken to hospitals in the area. The injuries ranged from abrasions to fractures to collapsed lungs. Five people were in critical condition and five were in severe condition, while 14 people had injuries considered minor, Rowling said.