A plane plunged into the stands at an air race event in Reno in what an official described as a "mass casualty situation."
A medical official said more than 75 are injured, at least 25 critically, but there's no word on any deaths at this moment.
Video of the crash showed a horrific scene of bodies and wreckage at the front of the stands.
An official says the pilot of a World War II era fighter that crashed into the grandstands was killed in the wreck.
Mike Houghton, president and CEO of the Reno Air Races, said at a news conference that pilot Jimmy Leeward of Ocala, Fla., died in the crash after apparently losing control of the aircraft.
Leeward is the owner of the Leeward Air Ranch Racing Team and is a well-known racing pilot. His website says he has flown more than 120 races and served as a stunt pilot for numerous movies, including "Amelia" and "Cloud Dancer."
Leeward also is a real estate salesman.
He died when the P-51 Mustang he was flying crashed into a box seat area at the front of the grandstand at the National Championship Air Races at about 4:30 p.m.
The National Championship Air Races draws thousands of people every year in September to watch various military and civilian planes race.