Chinese regulators have rebuked fashion brand Zara, Delta Air Lines and medical device maker Medtronic for calling Taiwan a country on their websites in a new show of Beijing's intense sensitivity about the self-ruled island.

Zara, Delta and Medtronic were ordered Friday to remove the "illegal content" and issue public apologies. The airline regulator told other carriers to check their own websites.

Beijing claims Taiwan as part of its territory and regularly lashes out at publishers of books, maps and other materials that refer to it as a country.

Earlier, the hotel chain Marriott was ordered to shut down its mainland China website and app for a week after a customer survey included Taiwan, Tibet and Hong Kong among a list of countries.