Several explosions have been reported at the SpaceX Falcon 9 launch pad at Cape Canaveral Air Force Station in Florida.
Pictures and footage show an explosion on the launch pad, while plumes of smoke can be seen coming from an area believed to be the air force station.
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 said the rocket had been unmanned at the time of explosion, which shook buildings nearby, Newsday reported.
In a statement carried by Florida Today, Space X said: "SpaceX can confirm that in preparation for today's static fire, there was an anomaly on the pad resulting in the loss of the vehicle and its payload.
"Per standard procedure, the pad was clear and there were no injuries."
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.
The first of the explosions 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.