Authorities have launched in investigation after nine circus acrobats were seriously injured when a rig collapsed during a show in Rhode Island, shocking spectators.

The all-female team with the Ringling Bros. and Barnum & Bailey Circus were hanging from a metal platform by their hair when it gave way and fell on top of them at the Dunkin’ Donuts Center in Providence.

According to VOA, the performers did not scream as the platform collapsed and they plunged 12m to the floor, but there was a collective gasp from spectators, unsure whether the fall was part of the act.

All the performers sustained serious injuries but are reported to be recovering well in hospital and none of the injuries appear to be life-threatening.

Investigators have not yet determined the cause of the accident.