Several explosions have been reported at the SpaceX Falcon 9 launch pad at Cape Canaveral Air Force Station in Florida.
Pictures have been circulating on social media reportedly showing the launch pad, while plumes of smoke can be seen coming from an area believed to be the air force station.
More than one source has suggested the explosion was the Falcon 9 rocket itself.
NASA has confirmed the blast took place during a test firing of the rocket ahead of a planned launch this weekend, when the rocket was set to hoist an Israeli satellite.
The space agency also confirmed the rocket had been unmanned at the time of explosion, which shook buildings nearby, Newsday reported.
The Falcon 9 thrust rocket was set to launch on Saturday, although poor weather had threatened the date for what would be the ninth launch of a Falcon 9 rocket this year.
There has been no word as yet from SpaceX staff about the explosions, the first of which is reported to have happened at around 9am (2pm BST) local time, with the second around 9.20am.
Ahead of the planned launch at the weekend, SpaceX founder and CEO Elon Musk had tweeted about what would have been a milestone launch for the company.
More to follow
