"A stage at the Indiana State Fair collapsed Saturday. At least a dozen were hurt, according to the Indianapolis Star newspaper.
The country music duo Sugarland, who was slated to appear on stage Saturday, tweeted that they were okay: "We are all right. We are praying for our fans, and the people of Indianapolis. We hope you'll join us. They need your strength."
A witness told CNN that inclement weather played a part in the incident, which was posted on Youtube.
"A big gust of wind came through. You could see a lot of people panicking. All the scaffolding and speakers - all that came crashing down - and the whole stand just collapsed," Aaron Richmann said.
Video from CNN affiliate WTHR showed flashing lights and emergency vehicles on the scene.
The National Weather Service issued a hazardous weather outlook for central Indiana Saturday evening. "Thunderstorms may be severe with damaging winds and large hail as the main threats," the weather service said. "The storms will also produce dangerous lightning and brief heavy rainfall."
The weather service said thunderstorms were possible for the area Sunday."
