Two planes taking part in an airshow in front of crowds collided in mid air, causing a huge fireball to rise into the sky.
The two aircraft were taking part in the popular Wings Over Dallas Airshow at Dallas Executive Airport in Texas when the incident happened at around 1.45pm local time.
Shock footage showed the planes, said to be a Boeing B-17 Flying Fortress and a Bell P-63 Kingcobra, in the skies over the event when one flew into the other, causing both to fall to the ground and explode.
A further video showed the smaller plane shearing off the tail section of the flying fortress.
Dallas Executive Airport posted on Twitter: "There has been an incident at Dallas Executive Airport during the CAF Airshow and Dallas Fire and Rescue is responding.
"More information will follow."
Seconds later a massive fireball was seen as shocked crowds looked on.
Onlookers were heard gasping in shock in the moments after the incident, with one saying: "Oh no."
The condition of the pilots aboard both aircraft is unknown, although the incident was so close to the ground there was no time for them to escape in their ejector seats before they plummeted to the ground.
Dallas Fire-Rescue reported an Alert 3 – Aircraft Emergency, after the mid-air collision between the two planes.
Emergency crews rushed to the scenes at the airport as road, including the US 67, were closed. Around half an hour after the tragedy remaining members of the public were asked to leave the event which was cancelled.
Television presenter Oli Pettigrew said: "Awful. B17 just went down at Wings Over Dallas. So sudden. Everyone is shaken.
"Tragic."
One shocked person said: "Hearing now of the collision of the Commemorative Air forces B-17 bomber and P-39 King Cobra fighter plane.
"Saw video and am certain no one could have survived this tragic air accident at the air show in Dallas Texas today.
"Please pray for the victims and their families."
Another added: "Clearly an accident as the pilot of the P51 could not see the B17 at all and was way wide of the leading group not seen in this video.
"Neither plane had a chance. I hope this doesn't end air shows in the US, this is really bad."
A spokesman for the Federal Aviation Authority said: "A Boeing B-17 Flying Fortress and a Bell P-63 Kingcobra collided and crashed at the Wings Over Dallas Airshow at Dallas Executive Airport in Texas around 1:20 p.m. local time Saturday.
"At this time, it is unknown how many people were on both aircraft.”
