The pilot of a small advertising blimp was seriously burned when the aircraft crashed at the US Open golf tournament, authorities said.
The man was the only person aboard when the craft went down shortly before midday at the Erin Hills golf course in Erin, Wisconsin.
The blimp went down in an open field near the course.
A statement from the Washington County Sheriff's Office says the pilot was taken to a hospital by medical helicopter.
The statement says the blimp was on fire or smoking and went down rapidly.
The sheriff's office asked the Federal Aviation Administration and National Transportation Safety Board to help investigate the cause.
It also said its initial investigation shows the blimp may have experienced mechanical problems before the crash.
First responders used utility vehicles to reach the crash site.
Aerial video from a television news helicopter shows pieces of the flattened blimp on the field along with charred metal and grass.
Golfer Brandt Snedeker said he spotted something while on the course.
"Yeah. My caddie made a comment on the ninth hole. He said the blimp is not looking good.
"I guess it was nose down. I saw a puff of black smoke. I didn't know it was the blimp. It's not good. Glad everybody is okay," he said after finishing his round.
The blimp, operated by Florida-based AirSign, was used for advertising as it floated above the golf tournament and had been airborne for several hours before it went down, authorities said.
Justin Maynard, a sales manager for AirSign, said the company's operations team on the ground in Erin had no more definitive information on the pilot's condition, other than the pilot was expected to be okay.
He could not confirm witness accounts that the pilot skydived from the blimp and said the aircraft's pilots do not regularly carry parachutes.
The Open is one of golf's four majors.