MOJAVE, Calif. (TheBlaze/AP) -- A Virgin Galactic space tourism rocket exploded after taking off on a test flight in Southern California's Mojave Desert, a witness said Friday.

The Kern County Sheriff's Office confirmed one pilot aboard died and the second was airlifted to the hospital with "moderate to severe" injuries, according to the Wall Street Journal's Jon Ostrower.

Virgin Galactic said its SpaceShipTwo "suffered a serious anomaly resulting in the loss of the vehicle." The company had tweeted earlier Friday morning that SpaceShipTwo was flying under rocket power.

"Virgin Galactic’s partner Scaled Composites conducted a powered test flight of SpaceShipTwo earlier today," the company said in a statement. "During the test, the vehicle suffered a serious anomaly resulting in the loss of the vehicle."

Picture showing apparent crash of Virgin Galactic #spaceshuttle via @foxnews TV pic.twitter.com/kV46U0pFAk

— Jonathon M. Seidl (@jonseidl) October 31, 2014

Ken Brown, a photographer who witnessed the crash, said the space tourism craft exploded after it was released from a plane that carries it to a high altitude.

The company founded by British billionaire Richard Branson would not say what happened other that it was working with authorities to determine the cause of the "accident." Branson tweeted that he was flying to the Mojave "immediately to be with the team."

The National Transportation Safety Board tweeted that it was sending a team to investigate the crash site.

Picture of what appears to be a parachute from #SpaceShipTwo via @ABC7JulieSonepic.twitter.com/as0RYJYYHX

— Jonathon M. Seidl (@jonseidl) October 31, 2014

Virgin Galactic has been the front-runner in the fledgling space-tourism industry.

SpaceShipTwo was designed to be carried aloft by a specially designed jet and then released before igniting its rocket for suborbital thrill ride into space and then a return to Earth as a glider.

Virgin Galactic, once it finished developing its rocket ship, was going to launch space tourism flights from the quarter-billion-dollar Spaceport America in southern New Mexico.

This post has been updated.