Two vintage World War Two-era planes have collided and crashed at an air show in the US state of Texas.
Footage shows the aircraft striking each other at a low altitude, breaking one of the aircraft in half. A fireball can be seen as it hits the ground.
The planes – one of them a Boeing B-17 Flying Fortress – were taking part in a commemorative air show near Dallas.
It was not immediately clear how many people were in the two aircraft, or if anyone survived.
The Federal Aviation Administration said it will investigate the crash at the Wings Over Dallas Airshow on Saturday, which describes itself as the US’s premiere WW2 airshow.
The three-day event was being held in honour of Veterans Day, which was on Friday.
Dallas Mayor Eric Johnson called it a “terrible tragedy”.
“The videos are heart-breaking,” he tweeted. “Please, say a prayer for the souls who took to the sky to entertain and educate our families today.”
The number of casualties are not yet confirmed, he said, but added that nobody on the ground had been reported injured.
The event’s website states that several planes had been scheduled to do a flyover demonstration on Saturday.
The B-17 bomber played a major role in winning the air war against Germany in WW2.
The second plane, a P-63 Kingcobra, was a fighter aircraft used in the same war, but used in combat only by the Soviet Air Force.