A fire on a Southwest Airlines plane forced passengers to evacuate before takeoff at a Southern California airport, wrote U.S. News.

Officials from John Wayne Airport say the crew of the Boeing 737 decided that the 139 passengers should evacuate Monday night using the aircraft's emergency slides just after the plane had pushed back from the gate.

Federal Aviation Administration spokesman Allen Kenitzer says the blaze was in the airliner's auxiliary power unit and was extinguished with the plane's fire suppression system. The auxiliary power unit provides power to start the aircraft's main engines and serves as backup power in some situations.

It forced a partial shutdown of the airport's taxiway, but airport operations are back to normal.