The White House slammed China’s demand that US airlines stop listing Taiwan, Hong Kong, and Macau as countries separate from China on their websites, calling it “Orwellian nonsense” on Saturday.

The remarks came at a sensitive time in US-Chinese relations — the day after the two countries failed to secure any meaningful agreement during high-level talks intended to prevent the outbreak of a trade war.

In late April, the Chinese government sent dozens of foreign airlines a letter demanding that they change the way they refer to Taiwan, Hong Kong, and Macau on their websites and other materials within 30 days — and threatened to disrupt their operations in China if they didn’t comply.

China doesn’t like that these airlines, some of which are American, list those territories as countries separate from China in places like drop-down menus for flight destinations on their websites.

Here’s why: Taiwan is a democratic and self-governing island off the coast of China that China sees as a renegade province. The US government’s policy for decades has been to have only unofficial diplomatic ties with Taiwan, implicitly acknowledging China’s claim to Taiwan as its territory. Hong Kong and Macau are former European colonies that China controls, but they’re highly autonomous — they have separate currencies, financial systems, and elected lawmakers.

On Saturday, White House press secretary Sarah Huckabee Sanders issued a statement firmly rejecting the Chinese government’s threats to US airlines over the way it lists the territories, characterizing it as “Chinese political correctness.”

“This is Orwellian nonsense and part of a growing trend by the Chinese Communist Party to impose its political views on American citizens and private companies,” Sanders said in the statement.

China fired back on Sunday. “No matter what the US side says, nothing will alter the objective fact that there is only one China in the world, and that the Hong Kong, Macau and Taiwan regions are inseparable parts of Chinese territory,” Geng Shuang, a spokesperson for the Chinese Ministry of Foreign Affairs, said.

The US and China are on the brink of a trade war. This doesn’t help.

This isn’t the first time China has lashed out over this issue — in January, it shut down Marriott International’s website in China for a week because the site referred to Tibet, Taiwan, Hong Kong, and Macau as separate countries in a questionnaire for customers.

But this current spat is adding to growing tensions between the US and China, which are standing on the brink of a trade war. The US has objected to the way the Chinese government subsidizes many of its industries, and how it forces US companies trying to do business in the country to hand over their intellectual property to Chinese companies.

In April, President Trump threatened to impose sweeping punishing tariffs on up to $150 billion worth of Chinese goods to pressure Beijing on the intellectual property issue. China responded by saying it will fight “at any cost” and take “comprehensive countermeasures” to Trump’s moves.

Last week, top officials from the US and Chinese governments held talks to try to resolve some of the trade issues and avoid the tariffs, but they agreed on little except to continue talking. If no agreement is reached in the coming months, things could get messy fast.