RENO, Nev. — A vintage World War II-era fighter plane plunged into the edge of the grandstand Friday at an air-racing show, killing at least three people, injuring more than 50 spectators and creating a horrific scene strewn with body parts and smoking debris.

The cause of the crash at Reno-Stead Airport wasn't clear, but an official with the National Championship Air Races and Air Show said there were indications mechanical problems were involved.

The plane, flown by Jimmy Leeward, 74, a renowned air racer and Hollywood stunt pilot, spiraled out of control and appeared to disintegrate upon impact. Bloodied bodies were spread across the area as people tended to victims and ambulances arrived.

Maureen Higgins, of Alabama, who has been attending the show for 16 years, said the pilot was on his third lap when he lost control.

She was sitting about 30 yards away from the crash and watched as the man in front of her started bleeding after a piece of debris hit him in the head.

"I saw body parts and gore like you wouldn't believe it. I'm talking an arm, a leg," Higgins said. "The alive people were missing body parts. I am not kidding you. It was gore. Unbelievable gore."

Among the dead was Leeward, of Ocala, Fla., a veteran airman and stunt pilot who nicknamed his P-51D Mustang fighter plane the "Galloping Ghost," according to Mike Houghton, president and chief executive of Reno Air Races.

Renown Regional Medical Center spokeswoman Kathy Carter confirmed that two others died, but did not provide their identities.

Stephanie Kruse, a spokeswoman for the Regional Emergency Medical Service Authority, said emergency crews took a total of 56 injured victims to three hospitals. She said the crews also observed a number of people being transported by private vehicle who were not included in the official count.

Kruse said of the 56 at the time of transport, 15 were considered in critical condition, 13 were in serious condition with potentially life-threatening injuries, and 28 had nonserious or non-life-threatening injuries.

A video shot by a spectator shows the small, brightly colored plane high overhead with its wings pitched almost perfectly vertical. Suddenly, brown smoke billows from the back of the plane, and almost immediately the plane shoots to the ground.

The P-51 Mustang, a class of plane that can fly at speeds of more than 500 mph, crashed into a box-seat area in front of the grandstand about 4:30 p.m., race spokesman Mike Draper said. Houghton said Leeward appeared to have "lost control of the aircraft," though details of why that happened weren't known.

Speaking at a news conference hours after the crash, Houghton said there appeared to be a "problem with the aircraft that caused it to go out of control." He did not elaborate. He said the rest of the races have been canceled as the National Transportation Safety Board (NTSB) investigates.

KRNV-TV weatherman Jeff Martinez, who was near the air-show grounds, said the plane veered to the right and then "it just augered straight into the ground."

"You saw pieces and parts going everywhere," he said. "Everyone is in disbelief."

Tim Linville, 48, of Reno, said the pilot appeared to partially lose control of the plane when he veered off course and flew over the bleachers where Linville was sitting with his two daughters.

"I told the girls to run, and the pilot pulled the plane straight up, but he couldn't do anything else with it," Linville said. "That's when it nose-dived right into the box seats."

Linville said that after the plane went straight up, it barrel-rolled and inverted downward, crashing into an area where at least 20 people were sitting.

"If he wouldn't have pulled up, he would have taken out the entire bleacher section" and hurt thousands of people, Linville said.

Leeward, owner of the Leeward Air Ranch Racing Team, was 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."

In an interview with the Ocala (Fla.) Star-Banner last year, he described how he had flown 250 types of planes and had a particular fondness for the P-51, which came into the war relatively late and was used as a long-range bomber escort over Europe. Among the famous pilots of the hot new fighter was World War II double ace Chuck Yeager.

"They're more fun. More speed, more challenge. Speed, speed and more speed," Leeward said.

The National Championship Air Races and Air Show draws thousands of people to Reno every year in September to watch various military and civilian planes race. The event also has attracted scrutiny about safety. More than 15 pilots have died at the races in their 48-year history, according to the Reno Journal Gazette, but Houghton said this is the first time spectators have been injured.

The competition is like a car race in the sky, with planes flying wingtip-to-wingtip as low as 50 feet off the sagebrush at speeds sometimes surpassing 500 mph. Pilots follow an oval path around pylons, with distances and speeds depending on the class of aircraft.

This has been a deadly year for air shows. Last month, an aerial stuntman plunged 200 feet to his death in Harrison Township, Mich. Days before, a pilot was killed in Kansas City, Mo., as his plane spiraled into a fiery crash after he could not complete a stunt meant for a show.

Material from The New York Times and Los Angeles Times is included in this report.