RENO, Nev. - The death toll in the crash of a vintage World War Two fighter plane near the grandstand at a Nevada air race has risen to nine, authorities said on Saturday.

In Martinsburg, West Virginia, another vintage US military plane went down in a fireball at an air show on Saturday, killing the pilot. There were no other casualties.

In the Reno crash, two people who died of injuries at hospitals and seven died on the tarmac following the Friday night crash, Reno Deputy Police Chief Dave Evans said. More than 50 people were injured. Officials said previously the crash killed at least three people.

People rush to help injured spectators following the crash of a vintage World War Two P-51 Mustang fighter plane near the grandstand at the Reno Air Races in Reno, Nevada, September 16, 2011. [Photo/Agencies]

The pilot, Jimmy Leeward, 74, was among those killed when his P-51 Mustang dubbed the "Galloping Ghost" crashed into a box seat area in front of the main grandstand, said Mike Draper, spokesman for the 48th Annual National Championship Air Races, also known as the Reno Air Races.

"It was like a war zone where the box seats were," Draper said.

Of the 35 injured in Reno, six were hospitalized in critical condition on Saturday, two were in serious condition and five in fair condition. One person was listed in good condition, and others had been discharged.

Investigators from the National Transportation Safety Board and Federal Aviation Administration were on the scene of the crash at an airfield north of Reno.

Proximity to the planes is a draw for the race, which advises on its website, "Always remember to fly low, fly fast and turn left."

Draper said the planes sometimes fly at high speeds "about 50 feet (15 metres) off the ground and it's an exciting, exciting sight."

The thrill has been a deadly one on occasion, with a total of 28 people killed in the history of the race flown every year in Reno since 1964, Draper said.

"The Reno Air Racing Association extends its most sincere heartfelt condolences and sympathies to all of those affected by yesterday's tragic events," the association said in a statement.

People rush to help injured spectators following the crash of a vintage World War Two P-51 Mustang fighter plane near the grandstand at the Reno Air Races in Reno, Nevada, September 16, 2011. [Photo/Agencies]

Leeward was the son of a pilot and his own sons have also flown planes. He worked as a stunt pilot on some movies, including the 2002 release "Dragonfly."

The NTSB also was investigating the Martinsburg crash, which came as six T-28 aircraft were flying in formation at the Thunder Over the Blue Ridge Open House & Air Show. A witness said one of the planes dropped and then rolled onto its side before crashing.

The T-28 was used as a trainer by the Navy and Air Force between 1950 and 1984.

The Reno and Martinsburg crashes were the latest in a spate of fatal air show accidents since August.

Last month, the pilot of an aerobatic airplane died in a fiery crash in front of shocked onlookers at a weekend air show in Kansas City, Missouri. In Michigan last month, a wingwalker at an air show near Detroit plunged about 200 feet (60 metres) to his death as he tried to climb onto a helicopter in midair.