A vintage P51 Mustang crashed into spectator seating at the Reno National Air Races earlier today. Reno officials described the aftermath of the crash as a "mass casualty" situation. UPDATED 4:45 PM EST

The aircraft had been competing in the races' Unlimited class, which includes heavily modified World War II vintage aircraft. According to the latest reports three people, including the pilot, have been confirmed dead by a local hospital [UPDATE: Police now say a total of nine people have died] and 50 are being treated for serious injuries, many life-threatening. Officials say the total number of injuries could top 75, once information from a number of hospitals is tallied. Reno-area hospitals are asking the public to donate blood, particularly Type O, to support their supply levels as they care for the many injured.

Witnesses have described the carnage at the scene in graphic terms, with many of the injured bleeding and missing body parts. "It was gore," one witness said. "Unbelievable gore."

The National Transportation Safety Board has taken over the crash investigation.

At the controls of the plane was veteran Hollywood stunt pilot Jimmy Leeward, 74 (original reports had listed his age as 80), who has been, according to his Facebook page, racing airplanes since the mid-seventies and the Galloping Ghost has raced since 1946, the longest racing career of any other active pilot or aircraft."

According to the Associated Press, some on the scene credit Leeward with preventing the crash from being more deadly. "If he wouldn't have pulled up, he would have taken out the entire bleacher section," one eyewitness said.

Chilling video of deadly Reno air race crashS

This is a picture of Leeward from his Facebook page.

The AP reports KRNV-TV weatherman Jeff Martinez, who was just outside the air race grounds at the time, said the plane veered to the right and then "it just augered straight into the ground."

The National Championship Air Races draws thousands of people every year in September to watch various military and civilian planes race. Planes fly wingtip-to-wingtip, following an oval path around a course of pylons, sometimes buzzing the ground as close as 50 feet, at speeds in excess of 500 mph.

Below, CBS has an interview of someone at the air show who sat next to the family of Leeward as his plane crashed into the ground.