WASHINGTON (AFP) - Nine acrobats were seriously injured on Sunday when a platform collapsed during an aerial hair-hanging act during a circus performance filmed by spectators in Rhode Island.

Eight of the female acrobats, performing during a Ringling Brothers and Barnum and Bailey Circus show in Providence, Rhode Island, were meant to hang by their hair in chandelier-like fashion.

The circus's parent company Feld Entertainment said the crash was under investigation.

"There was an accident during the hair hang act. All performers in the act received immediate medical attention and were transported to a local hospital for further care," Feld Entertainment said in a statement.

It said the 11am (11pm Singapore time) performance was stopped after the accident and the two other performances scheduled for the day had been cancelled.

Shortly after the platform's curtain dropped, the metal apparatus collapsed suddenly, and the women fell 25 to 40 feet (eight to 12 meters), landing on another performer on the ground, the Providence Journal cited police as saying.

They were rushed to hospital, where they were being treated in critical condition but with non-life threatening injuries.

A video posted on YouTube by an apparent spectator showed the structure crashing to the ground shortly after it nearly completed its ascension toward the ceiling of the Dunkin' Donuts Center.

"Everybody's conscious. Everybody's doing well. We ask everybody to pray for the girls," Ringling's Legends tour general manager Roman Garcia told reporters.

The circus website's describes the Medeiros Troupe as "hairialists" from the US, Brazil, Bulgaria and Ukraine who "perform a combination of choreography and cut-ups including spinning, hanging from hoops, and rolling down wrapped silks, all while being suspended 35 feet in the air by their hair alone."

"In this hair-raising act, audiences will even see the weight of three girls held aloft by the locks of only one of these tangled beauties," the website added.

Feld Entertainment spokesman Stephen Payne told CNN that "something went very wrong," noting that the apparatus had been used 12 to 14 times a week for months.

"So we're very concerned about what type of equipment failure took place," he added.