China has warned its people to think twice before visiting the United States, citing trade tensions. It also told its students to be careful about studying there and accused two American universities of hacking. And it has vowed to cut down on the number of Hollywood films that can be shown in China.

The trade war between the United States and China is already eroding far more than just economic ties. The rapid expansion of the battlefield, from trade to culture and education, underscores how fragile the relationship between the United States and China has become.

The United States, for its part, has revoked some Chinese student and scholar visas, as part of a broader targeting of international students by the Trump administration. While the moves were not directly related to the trade dispute, some conservatives have suggested linking them: Donald Trump Jr., the president’s son, posted online last week that it was a “great idea” to expel all Chinese students as retaliation for China hitting back with its own tariffs.

For decades, the flow of students, travelers, artists and businesspeople between the countries served as a steadying force, even when political or economic tensions flared. But as relations have deteriorated in recent years, both countries have started to turn those ties into bargaining chips, too.

“This is an emotional reaction, not a rational one,” said Shen Dingli, a Shanghai-based international relations scholar. “Rationally, the more tense China-U.S. trade relations become, the more both sides need to keep an overall balance, to avoid a full-on conflict.”

Until recently, both the United States and China had been trying to rehabilitate those softer exchanges, perhaps because they had gotten a glimpse of how dangerous their absence could be.

During Mr. Trump’s first term and the early years of President Joseph R. Biden’s, relations plunged to their lowest point in decades, inflamed by the coronavirus pandemic, disputes over Taiwan and an alleged spy balloon. At the same time, the yearslong closure of China’s borders during the pandemic led to a freeze of interpersonal exchanges.

When Mr. Xi and Mr. Biden finally met in person in 2023 to try and thaw the relationship, they pledged to restore some of those exchanges, as a way to shore up ties. Mr. Xi said he would invite more American students to China. American officials promised that they welcomed Chinese students.

Economic and political considerations were always inextricable from these détentes. Amid a lackluster economy, China last year allowed the highest number of foreign movies to be imported since 2019; official media noted that imported films would improve box office sales. American musicians who performed in China brought tourism to their host cities. China was eager to project itself as open as it tried to woo back foreign investors.

In the United States, Chinese students — who make up one-quarter of international students there — are a vital source of funding for American universities. In 2023, they contributed about $14.3 billion to the American economy, according to U.S. government data.

Still, both sides vaunted the ties as worthwhile in their own right. “The China-U.S. relationship has experienced ups and downs,” an article in Chinese state media said, “but China’s steadfast commitment to promoting friendly exchanges between the peoples of China and the U.S. has remained unchanged.”

Now, those promises are fading.

To retaliate for American tariffs, China has announced levies of its own, export controls, bans on certain American companies doing business in China — and the import of fewer Hollywood movies.

The government made clear that it expected — and might encourage — the economic frostiness to spill over to attitudes toward the United States in general. The tariffs would “inevitably reduce how favorably Chinese audiences view American films,” the national film administration said.

A day earlier, China’s culture and tourism ministry had warned travelers to “fully assess the risks” of visiting the United States, given the “deterioration of Sino-U.S. economic and trade relations.”

A separate warning from the education ministry did not mention the trade war, instead focusing on legislation passed in Ohio targeting academic collaborations with China. But it was published the same day as the tourism warning, and was the first alert the ministry had issued to Chinese students going abroad since 2021.

On Tuesday, Chinese state media separately accused the University of California and Virginia Tech of taking part in cyberattacks on the Asian Winter Games, which China hosted earlier this year. (The authorities also said they had added three people supposedly affiliated with the U.S. National Security Agency to a wanted list. Hashtags encouraging people to report clues about American spies trended on social media.)

The universities and the American Embassy in Beijing did not immediately comment.

Wang Li, a study abroad consultant in Beijing, said that she had been inundated by messages from parents and students in the last week. She hosted a livestream with 1,800 viewers to discuss the education ministry’s warning on Monday, where she addressed questions about whether people could still apply for visas or whether it was advisable to do so.

“This was all very sudden,” Ms. Wang said in an interview, referring to both the ministry’s warning and the American government’s visa revocations of many international students, including from China. “So it has caused panic.”

On Chinese social media, some users have said they were debating whether to cancel trips to the United States over the upcoming five-day May Day holiday. They cited fears of being turned away at the border and of general animosity toward China.

Da Wei, a professor of international relations at Tsinghua University in Beijing, said the travel and study notices were a warning shot to Washington from the Chinese government. He noted that they were not outright bans but also acknowledged that the countries were on the route to escalation, and that China was signaling that it could go further.

“Once you lose control, everything could happen, and it could be dangerous,” he said. “So I think the logic behind the Chinese side’s actions is kind of warning that you should not expand it to other areas.”

But Professor Da also noted that there were real reasons for Chinese students to worry about going to the United States. Government officials under both Democratic and Republican administrations have accused Chinese scholars of being spies. Mr. Da said that he himself has been stopped for extended questioning at the U.S. border multiple times.

Florida has restricted public universities from hiring Chinese citizens. A bill in the House of Representatives would bar any Chinese nationals from studying in the United States, though it is unlikely to pass.

Republican lawmakers have also demanded that several universities provide information on the finances and research of their Chinese students.

Ms. Wang, the study abroad consultant, said the tensions had scared off even people who were most eager to build connections with the United States.

“Many students, even if they look up to the freedom, tolerance and rich academic resources of the United States, feel they have to change directions,” she said.

On her livestream, she urged her viewers to keep their options open by also applying to Australian or European universities as backup.

“Leave yourself a safety net, OK?” she said.

Siyi Zhao contributed research.