(AP) – The National Transportation Safety Board on Sunday said it is gathering information about the evacuation of a Frontier Airlines plane after it hit and killed a person on the runway at Denver International Airport during takeoff.

The plane, on route from Denver to Los Angeles International Airport, “reported striking a pedestrian during takeoff at DEN at approximately 11:19 p.m. on Friday,” according to a post on the airport’s official X account.

Passengers were evacuated via slides, and the emergency crew bused them to the terminal. An airport spokesperson said 12 passengers suffered minor injuries and five were taken to hospitals. The spokesperson did not provide details on how the passengers were injured. But some people on board expressed concern about the evacuation, including being stuck in the plane for several minutes as smoke filled the cabin and left on the tarmac in the cold once they were out.

“We are gathering information about the emergency evacuation to determine if it meets criteria for a safety investigation,” NTSB spokesperson Sarah Taylor Sulick said early Sunday, adding that the agency might have more details in a few hours.

Frontier Airlines didn’t respond early Sunday to a request for information about the evacuation.

The pedestrian, who authorities have still not identified, was hit two minutes after two minutes after jumping the fence and crossing the runway. The person is not believed to be an airport employee.

“We’re stopping on the runway,” the pilot tells the control tower according to the site ATC.com. “We just hit somebody. We have an engine fire.”

The pilot tells the air traffic controller they have “231 souls” on board and that an “individual was walking across the runway.”

The air traffic controller responds that they are “rolling the trucks now” before the pilot tells the tower they “have smoke in the aircraft. We are going to evacuate on the runway.”

Frontier Airlines said in a statement that flight 4345 was the one involved in the collision and that “smoke was reported in the cabin and the pilots aborted takeoff.” It was not clear whether the smoke was linked to the collision.

The airline said the plane was carrying 224 passengers and seven crew members.

“We are investigating this incident and gathering more information in coordination with the airport and other safety authorities,” the airline said.

Transportation Secretary Sean Duffy said in a post on X that the person “breached airport security at Denver Int’l Airport, deliberately scaled a perimeter fence, and ran out onto a runway.”

He added: “No one should EVER trespass on an airport.”

The incident came a day after a Delta Air Lines employee was killed while on the job at the Orlando International Airport. In a statement, the airline said the employee was killed Thursday night without providing details of the incident or the name of the employee.

“We are focused on extending our full support to family and taking care of our Orlando team during this difficult time,” the airline said. “We are working with local authorities as a full investigation gets underway to determine what occurred.”