77 years after the end of World War II, two planes used at the time collided and crashed at an air show in Texas. A Boeing B-17 “Flying Fortress” bomber collided with a P-63 Kingcobra fighter in the airspace over Dallas Executive Airport during the Wings Over Dallas Airshow, the American Federal Aviation Administration reported on Saturday.

Rescue workers are on duty, airport officials tweeted. According to the FAA, it was initially unclear how many people were on board the machines. A video posted on social media showed the fighter ramming the low-flying bomber, the planes catching fire and falling.

A large cloud of smoke formed over the crash site. Officials said they were investigating the cause of the crash.