An attempt by United Airlines to duck the sticky issue of Taiwan has invited rebuke from China’s foreign ministry.

After China told global carriers earlier this year to tweak their websites and list the separately ruled island as part of China—a directive the White House termed “Orwellian nonsense”—American airlines are still finding themselves in the crosshairs of China. United Continental Holdings Inc. has resorted to using currency codes instead for Taiwan, Hong Kong and Macau, a move the Middle Kingdom isn’t too pleased with.

“However flexible they may try to get, there’s simply no way to sidestep the one-China principle,” foreign ministry spokeswoman Hua Chunying told reporters in Beijing Thursday, referring to overseas firms operating in the country. “There’s only one China in the world and Taiwan is part of China. This is the objective fact, common sense and international consensus.”

As the geopolitical tussle for supremacy intensifies between the U.S. and China, global businesses are finding themselves in a spot over Taiwan—long among the fraught issues between Washington and Beijing. The island has now reemerged as a key friction point between the two powers, especially amid the Trump administration’s more vocal support for President Tsai Ing-wen, a leader pushing to maintain the island’s de-facto independence.

China and Taiwan have been ruled separately since Chiang Kai-shek’s Nationalist government fled to Taipei in 1949. China’s Communist Party regards the island as its territory to be taken by force if necessary.

The Civil Aviation Administration of China asked 44 foreign airlines to change their online references to Taiwan, Hong Kong and Macau to reflect these locations as part of China. For instance, Taiwan should be referred to as “China Taiwan” or the “China Taiwan region.” While almost all the airlines complied with the demand, China has said changes by United, Delta Air Lines Inc., American Airlines Group Inc., and Hawaiian Airlines are still incomplete.

A spokeswoman at the CAAC said the regulator had no comments to offer at the moment, while representatives for United couldn’t immediately comment.

In the drop-down menu of United’s China website, the mainland, Hong Kong and Taiwan are respectively referred to by the Chinese Yuan, Hong Kong Dollar and New Taiwan Dollar. Other destinations are still identified by country name.

Under United’s options for departure and arrival cities, country codes have been removed for cities in China and Taiwan, a change also adopted by the other three U.S. carriers.

While that has failed to sway Beijing, United has a won a fan elsewhere.

“We welcome measures that honor Taiwan’s sovereignty,” Andrew Lee, the foreign ministry spokesman in Taipei, said by phone. “We thank United Airlines for flexibility in handling the issue.”