More than 500 foreign students have had their U.S. visas revoked in recent weeks, as the Trump administration intensifies its crackdown on universities. NAFSA, a prominent association supporting international education and exchange, revealed to the Financial Times on Tuesday that it had tracked 500 visa cancellations based on reports from institutions nationwide.

“This is uncharted territory on so many levels,” said Fanta Aw, CEO of NAFSA. “The scale is unprecedented, and it’s deeply troubling because the lack of transparency is creating widespread anxiety.”

The Department of Homeland Security and the State Department have launched a wave of enforcement actions affecting international students across the country. Universities are often left in the dark, unaware that their students have been targeted, making it difficult to monitor cases or provide assistance.

Students whose visas are revoked by the State Department must leave the U.S. and reapply, facing increased scrutiny. Separately, Homeland Security has initiated “status terminations,” according to Aw, who noted that the appeals process in both scenarios remains murky. “We’re going to see a tsunami of legal challenges,” she warned.

There have also been multiple reports of foreign students and university staff being detained and threatened with deportation. As a result, several institutions are now advising students and faculty to avoid international travel, fearing unpredictable treatment upon reentry.

What began with students at elite universities such as Harvard, Stanford, and Columbia has since expanded to a broader range of colleges and universities across the U.S., Aw said. Those affected come from diverse national backgrounds and have been targeted for various reasons — including minor infractions like traffic violations.

Since Trump’s election, more U.S.-based faculty have started looking for jobs abroad, and a growing number of high school and college students are applying to international universities. The Central European University in Vienna reported a 25% increase in U.S. applicants for the upcoming academic year, while the University of Toronto noted a “meaningful” rise in interest from American students.

On Monday, 16 higher education associations formally requested a briefing from the Departments of Homeland Security and State, following disjointed directives that, in some cases, instructed students to “self-deport.”