Southwest Airlines has apologized after a mother claimed its staff mocked her five-year-old daughter, called Abcde, over her name.

A gate agent laughed at the name -- pronounced 'Ab-si-dee' -- and posted a picture of her boarding pass online, the girl's mother, Traci Redford, alleged.

"The gate agent started laughing, pointing at me and my daughter, talking to other employees. So I turned around and said, 'Hey, if I can hear you, my daughter can hear you, so I'd appreciate if you'd just stop,'" Redford told ABC News.

The incident allegedly took place at John Wayne Airport in Orange County, California, as the mother and daughter boarded a flight to El Paso, Texas.

She added that she later found out the picture of her daughter's boarding pass had been posted to Facebook.

A spokesman for the airline offered a "sincere apology to the family" in a statement emailed to CNN. "We take great pride in extending our Southwest Hospitality to all of our Customers, which includes living by the Golden Rule and treating every individual with respect, in person or online," he added.

"We have followed up with the Employee involved, and while we do not disclose personnel actions publicly, we are using this as an opportunity to reinforce our policies and emphasize our expectations for all Employees," the spokesman said.