The Chinese Ministry of Education has warned Chinese students about studying in the United States, referencing an increase in delays and further complications regarding visa processing.

The warning comes during a protracted trade war and heightened tensions between China and the U.S., as well as concerns from some in Washington about espionage and intellectual property theft.

"The visa applications of some Chinese hoping to study in the United States have recently been restricted, with an extended reviewing process, shortened validity periods and increased rejection rate, which has affected their plans to study in the United States, or the completion of their study there," said Chinese Ministry of Education spokesperson Xu Mei.

The Ministry of Education also told students seeking to study at U.S. universities to "strengthen risk assessment."

Xu Yongji, another Ministry of Education official, told state broadcaster CCTV that 13.5% of all Chinese student visa applicants were "unable to make the trip as planned," citing complications with visas.

"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 told reporters on Monday.

Some lawmakers and policymakers in Washington have sought to restrict the number of Chinese international students attending American universities.In June of last year, the State Department shortened the length of visas from five years to one year for Chinese graduate students in the fields of robotics, aviation and advanced manufacturing. According to officials, the goal is to protect intellectual property and defend against espionage.

Ties to Chinese military

Congressional Republicans have also sponsored a bill that would prohibit individuals who are employed or sponsored by organizations with connections to the Chinese military from receiving student or research visas.

China is the largest source of international students in U.S. colleges, with 33.2% of all international students coming from China, according to the Institute for International Education.In the 2017-2018 year, this translated to 363,341 students, a 3.6% increase from the previous academic year.

Many educators have expressed concern over the Trump administration's stance toward international applicants for student visas. In a report by NAFSA: Association of International Educators, international education is a $39 billion industry. At NAFSA's annual conference last week, many claimed their enrollments had been in decline, according to reporting by VOA News.

In August 2018, Business Roundtable, an organization of CEOs, sent an open letter to then-Homeland Security Secretary Kirstjen Nielsen advocating for a change in immigration policy in regard to students from abroad.

"Inconsistent government action and uncertainty undermines economic growth and American competitiveness and creates anxiety for employees who follow the law. In many cases, these employees studied here and received degrees from U.S. universities, often in critical STEM fields," the letter read.

In April, FBI Director Christopher Wray alleged that China was using "graduate students and researchers" to conduct espionage.

"We need to focus even more on a whole-of-society approach because in many ways, we confront whole-of-society threats," Wray said.

U.S. President Donald Trump is set to meet with Chinese President Xi Jinping at a G20 summit in Japan later this month.