BELLEVUE — A pair of runaway horses in harness crashed into a Fourth of July parade float and collapsed, ending a rampage that injured nearly two dozen people and killed one, people at the parade said Monday.

Tammy Muller, 43, a bartender who works downtown, said she was watching the parade at an intersection when she heard screaming. She said she looked up, saw the horses and yelled, "back up!"

The frenzied animals sped past her and were heading for a large crowd including children who had gathered to pick up candy, when they crashed into the Maquoketa State Bank's float as it turned at the intersection.

The horses went down, and her boyfriend Dennis "Cowboy" Dunne jumped on one to hold it down, Muller said. She said he described the animals as quarter horses.

Mayor Virgil Murray said officials were working Monday to reconstruct exactly what happened at the parade, which he described as "bigger than Christmas" in the small Mississippi River town on the Iowa-Illinois border. The parade, which draws 3,000 to 4,000 people to the town of about 2,300, began about 10 a.m. Sunday. The rampage began sometime between 10:30 and 11:15 a.m., he said, and was over in minutes.

The horses got spooked after they rubbed heads and one's bridle fell off, police said. They ran about six blocks, moving up onto sidewalks and back into the road, plowing through children lined up along the street to watch the parade, Murray said.

People at the parade said the buggy hit a sign and overturned, dumping its four passengers. One, Janet Steines of Spragueville, died Sunday evening at the University of Iowa Hospital in Iowa City, according to the Hachmann Funeral Home in Bellevue. Her husband had been driving the carriage.

The horses continued to run after it came unhitched, Muller said. They were still harnessed together when they hit the float. She said they eventually got up and people led them down to the river to calm them down.

Sandie Crilly was helping her 8-year-old son, 12-year-old niece and 2-year-old granddaughter pick up Tootsie Rolls when someone yelled to get out of the way.

Looking up, she saw the panicked horses dragging a carriage charging toward them.

"I could see it was two horses," said Crilly, 46, of Willow Springs, Ill., who was visiting her parents in Bellevue. "I could see they were running at full speed and they were harnessed together and I knew we were going to most certainly get hit, and as soon as it happened, everybody was crying and screaming."

Someone pulled her granddaughter to safety, but Crilly said her niece broke her wrist and lost her two front teeth. At least 22 other people were injured, some critically, police and hospital officials said.

Many of them were children like Crilly's niece who were picking up candy from the street that had been tossed to them. Their injuries ranged from cuts and bruises to broken bones, concussions, collapsed lungs and other serious injuries, the Dubuque Telegraph Herald reported.

The injured were sent by ambulance and medical helicopter to hospitals in Dubuque, Maquoketa and Iowa City. Most were treated and released, but at least four people remained in critical condition early Monday, hospital officials said.

Paramedics treated victims at an art gallery in town and a triage area was set up near the Mississippi River, where volunteers held up tarps to shield the injured and paramedics from the sun and heat, Crilly said. Others brought the injured ice and water, she said.

"It was madness," Crilly said. "I mean we were in a triage. The town really came together. It was a huge community effort."

Murray said residents were shocked, and they've never had problems with having horses in the parade before.

"We've never really had any tragedy," the mayor said. "Usually our biggest nemesis is if it rains. That's what we're always worried about."

Iowa Gov. Chet Culver released a statement saying the victims were in his thoughts and prayers.

"I am especially saddened because the accident occurred during the events celebrating Independence Day, which is a day that should be filled with pride and joy for all Iowans and Americans," Culver said.