LOUISVILLE, Ky. -- A teenage girl's legs were severed above the ankle while on a thrill ride at a popular amusement park on Thursday, park officials said.

The accident happened around 4:45 p.m. on the Superman Tower of Power at Six Flags Kentucky Kingdom, said Six Flags spokeswoman Wendy Goldberg.

It is unclear at what point during the ride the girl, 13, was injured, Goldberg said. The girl was taken to University Hospital. There was no immediate word on her condition.

The ride lifts passengers 177 feet straight up, then drops 154 feet, reaching a speed of 54 mph according to the park's Web site.

The ride has been shut down indefinitely while park officials investigate what caused the accident. The rest of the park remained open.