Facebook satellite lost in SpaceX explosion at Cape Canaveral (VIDEO)

A Falcon 9 booster rocket exploded on the launch pad in Cape Canaveral, Florida, as tropical storm Hermine bore down on the area. An Israeli satellite that was to provide Facebook broadband to Africa was lost in the explosion, SpaceX confirmed.

"In preparation for today's static fire, there was an anomaly on the pad, resulting in the loss of the vehicle and its payload," SpaceX said in a statement Thursday morning.

SpaceX CEO Elon Musk said that the explosion occurred during the fueling phase, and originated "around upper stage oxygen tank," but the cause was still undetermined.

The blast shook buildings some distance away, according to witnesses who reported it on social media. Thick black smoke could be seen rising from the pad, while secondary explosions continued.

The plume of smoke was tracked on weather radar.

There were no casualties from the explosion, and no threat to the general public, said the US Air Force's 45th Space Wing, which controls the Cape Canaveral launch station.

Citing NASA security, one source reported that the rocket blew up during “wet dress rehearsal.” This is the type of pre-launch test that uses actual liquid propellant, but may or may not involve the payload.

Brevard County Emergency Management Office said there was no danger to the general public, and said the rocket exploded during a static test firing.

SpaceX’s next launch was supposed to be on Saturday, September 3, with a Falcon 9 rocket carrying the Israeli communications satellite Amos-6 into geostationary transfer orbit (GTO).

The satellite would have provided broadband internet coverage to sub-Saharan Africa, as part of an initiative spearheaded by Facebook.

Thursday's explosion did not involve a reused Falcon 9 booster. SpaceX announced on Tuesday that it would use a recovered rocket to launch a SES communications satellite "later this year," probably sometime in December.

The explosion will set back NASA efforts to use SpaceX vehicles for getting astronauts and supplies to the International Space Station, Bruce Gagnon, coordinator of the Global Network Against Weapons and Nuclear Power in Space, told RT.

“It’s a big setback,” said Gagnon. NASA is “trying to find someone to shuttle supplies and astronauts to the ISS, since the US has begun its recent demonization of Russia. That relationship, where Russia was delivering astronauts to the space station, has really been now cast aside. So SpaceX is going to be the predominant delivery service. This launch failure, with this explosion of the rocket, is really going to put a real crimp in NASA’s launch program.”