The Civil Aviation Administration of China earlier in the day posted a statement on its website demanding the U.S. carrier to issue an "immediate and public" apology and to investigate how the issue occurred.

"Delta recognizes the seriousness of this issue and we took immediate steps to resolve it," the company said in an emailed statement to Reuters.

"It was an inadvertent error with no business or political intention, and we apologize deeply for the mistake. As one of our most important markets, we are fully committed to China and to our Chinese customers."

(Reporting by Brenda Goh; Editing by Christian Schmollinger)