A Delta Air Lines flight was apparently struck by fireworks as it descended into Chicago Midway International Airport on Saturday evening, according to air traffic control audio and the airline.

“We just had a firework hit our plane,” the pilot of Delta Flight 1076 told controllers, according to the audio.

“We’re just hoping it was just a mortar that went off underneath, but definitely felt a big bang.”

The controller replied that there had been “multiple reports” of similar incidents and instructed the crew to head to the gate and inspect the aircraft for damage.

As a subsequent Southwest Airlines flight descended into Midway, a controller warned: “Welcome to the war zone.”