One person has died and another has been injured after a spaceship crashed in a California desert.
A spokesman for the Kern County Sheriff's office has said the co-pilot was killed and the pilot, who ejected, suffered "moderate to major" injuries after a Virgin Galactic spacecraft crashed in the Mojave Desert.
The pilot was found at the scene and taken to a local hospital.
The suborbital passenger spaceship is being developed by Richard Branson's Virgin Galactic.
It crashed during a test flight today at the Mojave Air and Space Port in California, officials said.
Only the two pilots were aboard the spaceship, which was undergoing its first powered test flight since January.
Earlier Virgin Galactic reported on Twitter that its SpaceShipTwo craft suffered an inflight "anomaly".
During the test, the vehicle suffered a serious anomaly resulting in the loss of SpaceShipTwo. WK2 landed safely. (2 of 4)
— Virgin Galactic (@virgingalactic) October 31, 2014We will work closely with relevant authorities to determine the cause of this accident and provide updates ASAP. (4 of 4)
— Virgin Galactic (@virgingalactic) October 31, 2014Thoughts with all @virgingalactic & Scaled, thanks for all your messages of support. I'm flying to Mojave immediately to be with the team.
— Richard Branson (@richardbranson) October 31, 2014
More than 800 people have paid or put down deposits to eventually fly aboard the spaceship, which is carried to an altitude of about 45,000 feet and released.
The spaceship then fires its rocket motor to catapult it to about 100km above Earth, giving passengers a view of the planet set against the blackness of space and a few minutes of weightlessness.
The vehicle is based on a prototype, SpaceShipOne, which ten years ago won the $10m (€8m) Ansari X Prize for becoming the first privately developed manned spacecraft to fly in space.
"During the test, the vehicle suffered a serious anomaly resulting in the loss of SpaceShipTwo," Virgin said in a tweet, adding: "We will work closely with relevant authorities to determine the cause of this accident and provide updates ASAP."
The crash was the second accident this week involving a commercial US space company.
On Tuesday, an Antares rocket built and launched by Orbital Sciences exploded 15 seconds after liftoff from Wallops Island, Virginia, destroying a cargo ship bound for the International Space Station.
