(CNN) -- The weekend accident that injured nine members of a circus troupe, along with two other people, during a Ringling Bros. performance in Rhode Island was caused by a malfunctioning clamp, authorities said Monday.
Providence Public Safety Commissioner Steven Pare didn't provide any additional details of what happened to cause the clamp to fail Sunday morning, sending eight performers plummeting some 25 feet to 35 feet to the ground.
A performer on the ground and two other people were also injured, officials said. Many suffered broken bones, officials said. Two of those hospitalized remained in critical condition Monday, CNN affiliate WPRI reported.
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A circus spokesman called the accident "unprecedented."
"We have never had an accident like this with this number of performers injured," said Ringling Bros. spokesman Steven Payne. "It really is a testament to, you know, their physical fitness and skills, that the injuries were not more severe than they were."
The injuries came after the failure of a rig holding eight members of the Medeiros Hair-Hang Act aloft by their hair. The rig collapsed as the audience looked on. Many suffered broken bones, Pare said Sunday. No spectators were hurt.
"I screamed. I'm like, that's not right," Chelie Barrie, a spectator, told WPRI. "You know, sometimes you're surprised and it's part of the show, but this clearly wasn't."
Rhode Island Hospital has confirmed that each of the eight women named by Ringling Bros. as part of the act are in the hospital: Viktoriya Medeiros, Widny Neves, Samantha Pitard, Viktorila Liakhova, Dayana Costa, Julissa Segrera, Stefany Neves and Svitlana Balanicheva.
The Medeiros Hair-Hang Act is touted on the Ringling Bros. website as a "one-of-a-kind act ... the brainchild of husband-and-wife team Andre and Viktoria Medeiros, (who) have devised and improved the mechanisms and methods making possible the myriad of maneuvers this troupe will perform for audiences."
"It is Andre's attention to every detail, even welding the three different rigs that the girls hang from, that keeps his troupe safe and sound each and every time the act is presented," according to the website.
The circus canceled both of its scheduled performances Monday amid the investigation, which Pare said is now being led by the federal Occupational Safety and Health Administration.
Payne said the circus is cooperating fully with investigators trying to understand what happened.
Elaine Alcorn, a circus performer who was not involved in the show, said "nothing is ever 100% sure" in a dangerous pursuit such as the circus.
"There can always be mistakes, there can always be failures in the rigging," she said.
It's something performers accept, she said.
"They don't call it death defying for nothing," she said. "As a circus performer it is our job to do the impossible, to stare death in the face and conquer it. We don't just do it for entertainment. We do it to inspire people, to inspire them to conquer their own fears or overcome their own obstacles."
CNN's Kristina Sgueglia, Nick Valencia, Adrienne Zulueta, Dominique Dodley, Susanna Capelouto, Mark Morgenstein and Dana Ford contributed to this report.
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