A woman said she found a swastika burned with butter onto a bun of a McDonald's chicken sandwich, according to various media organizations.
Charleigh Matice ordered the sandwich at a McDonald's drive-thru in Morehead City, N.C., last week, ABC News reported.
"Is this a joke? Does somebody really think they're funny?" Matice told WCTI.com.
In a statement e-mailed to USA TODAY Network on Monday evening, the McDonald's local owner apologized for the incident and said the employee involved had been fired.
"We are very sorry for the service that our customers received, and to be clear we have terminated the employee who was involved," said Dulcy Purcell, McDonald's operator in Morehead City. "We do not tolerate that kind of behavior at McDonald's, and it's not what we stand for personally as owners."
Initial efforts to reach Matice for comment have proved unsuccessful.