"Whatever the USA said can not change the fact that there is only one China in the world and Hong Kong, Macao and Taiwan are indispensable parts of Chinese territory", Chinese Ministry of Foreign Affairs spokesman Geng Shuang stressed, adding that companies need to "respect the country's sovereignty and territorial integrity" and "respect the Chinese people's national sentiments".
The White House said President Donald Trump "will stand up for Americans resisting efforts by the Chinese Communist Party to impose Chinese political correctness on American companies and citizens".
The letter to airlines offered more detailed instructions on how Taiwan should be described when compared with an earlier warning in January that Taiwan not be called a separate country.
China views the democratic island as a renegade part of its territory and has not ruled out the use of force to bring it back into the fold if necessary.
Spokesperson Geng Shuang noted that no matter what the USA side says, it will not change the fact that there is only one China and that Hong Kong, Macau and Taiwan are inalienable parts of China.
Un Clasico sans vainqueur mais avec beaucoup de saveurs
Il y a toujours un esprit de revanche, on dirait que les gens cherchent à ce que l'adversaire soit humilié en t'applaudissant. Karim Benzema est de moins en moins efficace et sa place au sein du Real Madrid est menacée par un transfert.
Usually, pressure is exerted by Beijing, which takes airlines to task for failing to identify China in their descriptions of Hong Kong, Macau and Taiwan. "We call on China to stop threatening and coercing American carriers and citizens".
On Monday, the United States embassy in Beijing joined the war of words by publishing a version of the White House statement in Mandarin on Weibo, the Chinese equivalent of Twitter.
Commenting on the changing situation between Taiwan and China, Taiwan Thinktank researcher Tung Li-wen (董立文) said that over the past 30 years, China has always resorted to political bullying and saber-rattling to intimate Taiwan, triggering resentment among Taiwan's people and pushing them away from China.
Koji Nagata, United Airlines' director for Asia-Pacific corporate communications, told the Post, however, that the company had passed the letter on to the White House.
The White House's latest statement was released as a high-level U.S. trade delegation, led by U.S. Treasury Secretary Steve Mnuchin, wrapped up a visit to China.
A spokesman for Airlines for America, a trade group representing United Airlines, American Airlines and other major carriers, said on Saturday it was working with the USA government to determine "next steps" in the dispute.