A young girl was was bitten by a support dog that was accompanying its owner on a busy passenger flight.

The incident occurred onboard a Southwest Airways service from Pheonix, Arizona, to Portland, Oregon, scheduled to takeoff at 11.45pm on February 21.

The young girl "about the age of six" was bitten on the forehead after she attempted to pet the animal, according to one eyewitness. The girl and her parents were forced to leave the aeroplane as medics bandaged her forehead, but were subsequently allowed to return to to her seat.

The passenger with the dog was asked to leave the flight and did not "argue or fight the decision to be removed."

Twitter user Todd R. took a picture of the incident and wrote: "@SouthwestAir flight 1904 allows a support dog on the plane, bites kid, paramedics now on plane. Why are dogs on the plane?! Never again will I fly SWA."

Southwest said "initial reports" suggested the support dog bit the young passenger after it was approached, causing "a minor injury."

"EMTs evaluated the child, who was cleared to continue on the flight. The dog and its owner remained in Phoenix as the aircraft departed approximately 20 minutes behind schedule. As always, the safety of our Customers is our highest priority," a spokesperson for the airline said.

Southwest was unable to tell IBTimes UK why the owner was travelling with a support animal but says it "welcomes fully trained emotional support animals accompanying a customer with a disability on our flights."