Students sit on the steps of Wilson Library at the University of North Carolina at Chapel Hill. (Jonathan Drake/Reuters)

China warned students on Monday to think about the “risks” associated with attending college in the United States, an apparent sign that the authorities in Beijing are expanding the boundaries of the trade war to include educational exchanges.

The warning comes as the Chinese government looks for ways to retaliate against the Trump administration for the tariffs it has imposed on $250 billion worth of goods from China, including fish and tungsten. 

Tentative plans are underway for President Trump and his Chinese counterpart, Xi Jinping, to meet at the Group of 20 summit in Japan later this month to try to find a way out of the protracted trade war. But analysts said that they will meet only if substantial progress has been made — and that there has been none so far.

Speaking to reporters in Beijing on Monday, Xu Yongji, an official from the Education Ministry, said that the Trump administration and Congress had “politicized some normal China-U.S. educational exchanges and cooperation activities.”

“[They] are cracking down on them under the banner of ‘China threat’ and ‘China infiltration,’ and they are stigmatizing Confucius Institutes as a tool for China,” she said, referring to the programs through which Beijing has sought to expand Chinese language and cultural studies into American universities.

“[They] are accusing Chinese students and scholars in the United States of launching ‘nontraditional espionage’ activities and causing trouble for no reason,” Xu said, advising current and potential students to “strengthen” their risk assessments before deciding to study in the United States.

Chinese students have made up an increasingly large proportion of international students in the United States in recent years, numbering more than 370,000 in the past academic year — or almost one-third of all international students. They have become a valuable source of income for many colleges.

 But the rate at which they are being rejected for visas is concerning the authorities here.

In 2018, 331 of the 10,313 students who applied to study in the United States on Chinese government scholarships were rejected, according to government figures. That amounted to a rejection rate of 3.2 percent. But in the first three months of this year, 182 of the 1,353 students who applied — or 13.5 percent — were unable to go because ofvisa problems, the China Scholarship Council statistics showed.

Furthermore, officials said that visas are taking longer to issue and are being issued for shorter periods.

This comes as the United States has revoked the 10-year visas of some Chinese scholars dealing with U.S. relations.

“These kinds of behaviors have already hurt the dignity of Chinese students studying in the United States and have seriously hurt the feelings of the Chinese people,” Xu said. “This American behavior is causing a cold snap in China-U.S. educational exchanges and cooperation.”

In recent days, the Chinese Internet has been busy with news that Chinese citizens will now be required to submit information about their social media accounts when applying for a U.S. visa. This includes sharing usernames for Chinese services including WeChat, Weibo and Youku, the visa department of China CYTS Tours wrote on its online accounts.

 The Chinese Embassy in the United States issued a notice on its website Sunday about the new requirement, reminding citizens to “truthfully provide the application materials.” 

No quick end is in sight for the trade war, which began when Trump vowed to close the United States’ roughly $400 billion trade deficit with China. He has imposed tariffs of 25 percent on $250 billion in Chinese imports and has threatened to add duties to the remaining $300 billion in goods that the United States imports from China.

The administration has also put Huawei, a Chinese telecom giant, on a blacklist that effectively bars U.S. companies from supplying it with computer chips, software and other components without government approval. 

Beijing responded by imposing tariffs on $60 billion worth of U.S. products, but has run out of American goods to tax. That has led it to take other reciprocal actions, including announcing a plan to establish a blacklist of “unreliable” foreign companies and organizations, effectively forcing companies worldwide to choose whether they would side with Beijing or Washington.

Liu Yang contributed to this report.