"Mass casualties" were reported at an air show after a plane crashed Friday into an area in front of a grandstand at the National Championship Air Races and Air Show in Reno, Nevada, a spokesman for the show told CNN.
Mike Draper said he's been told there are "likely fatalities," but it has not been determined how many or who they may be. The fate of the pilot, who was flying a P-51 Mustang, was not known, he said.
Video from the scene, posted on YouTube, showed a plane plummeting from the sky, sending up clouds of dust and debris.
Shocked spectators rose to their feet.
The P-51 plane, called the "Galloping Ghost," was taking part in a qualifying round in the "unlimited class" division of the air race when it went down around 4:15 p.m. PT Friday, Draper said. The final rounds had been slated for the weekend.
The aircraft was about a lap into the race when the pilot sent out a "Mayday signal" and pulled "out of the lap" before crashing into a box area that is in front of a grandstand at the "very large race field," located about 15 miles north of Reno, Draper said.
"It was clear that (the plane) was pulling up and was in distress," he said.
He added that authorities do not yet know why the aircraft went down.
Besides the Federal Aviation Administration personnel already there to assist the National Transportation Safety Board in any investigation, the show's spokesman said that National Guard members -- who were on-site practicing before the incident -- are helping emergency personnel to clear the area.
"There are people still being escorted out of that area with various injuries," Draper said.
Local fire officials are reporting multiple fatalities and critical injuries, according to Ian Gregor, a spokesman with the FAA.
He said the aircraft did not catch fire, but there was a wide debris field following the crash.
CNN's Mike Ahlers contributed to this report.
