United Airlines has fired a flight attendant who deployed an emergency evacuation slide on an airplane after it arrived in Houston this week and used it to exit a plane packed with passengers, an airline official said on Wednesday.

"She is no longer a United employee," said United Airlines spokesman Charlie Hobart.

The airline, a unit of United Continental Holdings Inc, did not identify the flight attendant. It said it believed she deployed the slide intentionally in the Monday incident but did not provide a reason as to why she did it.

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In a video shown on Houston TV station KPRC, the flight attendant tosses her bag out of a door behind the cockpit and slides down the slide. She grabs the bag and walks away from the plane, which was at full stop.

A photo of the airplane on the station's website shows it at the gate, with the slide deployed on the side opposite of the gate.

The flight, with 159 passengers and six crew members aboard, was from Sacramento to Houston's George Bush Intercontinental Airport. The airplane, a Boeing 737-900, was briefly taken out of service for maintenance and then returned to its scheduled use.

All the others aboard exited the plane without incident or injury.