BEIJING -- Delta Airlines has apologized for listing Tibet and Taiwan as independent countries on its official website and promised to take immediate measures to correct the mistakes.

Delta apologized deeply for the serious mistakes that have hurt Chinese people's feelings and it was taking immediate steps to resolve it, said a statement posted Friday night on the website of the Civil Aviation Administration of China (CAAC).

The US carrier said it will have a careful check for other possible errors and avoid such mistakes in the future.

In the letter of apology to the CAAC and on its official website, Delta said it is fully committed to China and Chinese customers as China is one of its most important markets.

The CAAC earlier in the day summoned representatives of Delta, urging the company to issue an immediate and public apology, and to investigate the incident thoroughly and publish investigation outcome in a timely manner.

On the Chinese version of Delta's official website, it listed Chinese territories, including Tibet and Taiwan, as "countries" in a drop-down menu.

The CAAC on Saturday asked all foreign airlines operating in China to conduct self-checks on their websites, mobile apps and other platforms for similar mistakes including regarding Hong Kong, Macao and Taiwan as "countries" in an online notice.

"If there are such cases, actions should be taken immediately to rectify the mistakes," the CAAC said, adding that it will examine the process.