An explosion has been reported in Florida at Nasa's SpaceX site, after tests on a unmanned Falcon 9 rocket.
Buildings several miles away are said to have been shaken by the blast, with multiple explosions continuing for several minutes. It is reported that the first blast sounded like lightning, followed by explosions.
Dark smoke was seen filling the sky. The test was routine, in advance of a planned launch on Saturday from Cape Canaveral Air Force Station.
The Falcon 9 was being prepared to launch the Amos 6 satellite, which is a communications probe for Israeli satellite operator Spacecom.
There have been no reported injuries.