A British Airways worker was killed and passengers had to be escorted off one of its planes after two vehicles collided on the tarmac at London Heathrow airport.

The crash on Wednesday involved two airfield vehicles and happened behind the BA aircraft, which was hemmed in at the parking stand as police started to investigate. One person, an engineer at the airline, died in the aftermath of the incident, Heathrow said in an emailed statement.

Passengers were taken off the BA jet and transferred to another one, according to the airline, which said a handful of other services were delayed. Heathrow, Europe's busiest hub, didn't cancel any flights.

"We can confirm that following a serious accident involving two vehicles on our airfield, an airport colleague has passed away," Heathrow said. "We will be fully cooperating with the police in the investigation which will follow."

A spokesman for the airport, which attracted 78 million passengers in 2017, said that there is no indication of terrorist involvement.

BA apologized to customers for delays to "a small number" of flights. "We are doing all we can to ensure they will be able to depart as soon as possible," the unit of IAG SA said in a statement.