FILE PHOTO: Delta planes line up at their gates while on the tarmac of Salt Lake City International Airport in Utah September 28, 2013. REUTERS/Lucas Jackson/File Photo

SHANGHAI (Reuters) - Delta Air Lines apologized on Friday and said it recognized the seriousness of the issue after it was criticized by the Chinese aviation regulator for listing Taiwan and Tibet as countries on its website.

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.”