'Broken' metal clamp involved in circus acrobat fall
Investigators are focused on a metal clamp as the potential cause of a collapsed circus apparatus which left two acrobats in critical condition.
Eight female acrobats plummeted up to 12m (40ft) when the scaffolding structure holding them fell in the US state of Rhode Island on Sunday.
The performers, from the US, Brazil, Bulgaria and Ukraine, were in the middle of a hair-hanging high-wire act.
The clamp was the only faulty equipment identified so far.
Federal safety investigators have not yet determined why it snapped, and have not officially labelled it the cause of the accident.
"We don't know if it was metal fatigue, if it wasn't properly positioned or something else," Providence Public Safety Commissioner Steven Pare told US media.
The steel clip - found in three pieces on the ground - was reportedly one of several pieces at the top of the apparatus which suspended performers in the air.
Acrobats Dayana Costa and Julissa Segrera have injuries said to include a pierced liver and neck fractures.
"The injuries fortunately don't appear to be life-threatening," Nicole Feld, executive vice-president of Ringling Bros and Barnum and Bailey parent company Feld Entertainment, told a local television station.
"A lot of them were awake, talking, communicating with us."
According to the circus website, the eight performers, known as "hairialists", feature in a "larger-than-life act... spinning, hanging from hoops, and rolling down wrapped silks all while being suspended 35ft in the air by their hair alone".
The collapse occurred during an act in which the eight performers hung from their hair "like a human chandelier", according to the circus.
"It just went crashing down... Everyone was freaking out. We heard this huge clatter and then we just heard the girls scream," witness Sydney Bragg, 14, told the Associated Press news agency.
Further performances were cancelled on Sunday and Monday as the circus worked with federal and local officials.
"We want to make sure all of our performers are safe," Stephen Payne, a spokesman for Feld Entertainment, said.
"An accident like this is unprecedented involving this number of performers," he added.