MOUNT PLEASANT, MI -- The Trump administration has stripped several current and former international students at Central Michigan University of their legal residency without notifying either the university or the students themselves, campus leaders said in a Friday afternoon email.

“This news is alarming and may be especially difficult for our international students, faculty and staff, who are valuable, important members of our community,” said the April 4 email signed by Central’s President Neil MacKinnon and Provost Paula Lancaster.

The U.S. Department of Homeland Security did not immediately respond to an inquiry about why the students’ legal residency had been revoked.

President Donald Trump ran on a promise to deport international students who had been involved in pro-Palestine demonstrations, and several have been detained over the past month, notably Mahmoud Khalil, who played a prominent role in protests at Columbia University, and Rumeysa Ozturk, a Tufts University doctoral student who was arrested on the street in a Boston suburb.

But the government seems to have expanded its efforts over the past two weeks. College officials around the country say hundreds of international students have had their legal residency status revoked, often without notice, many for minor infractions or for no clear reason at all.

“We’re doing them every day,” Secretary of State Marco Rubio told reporters last week .

“They’re visitors to the country,” he added, “If they’re taking activities that are counter to our foreign – to our national interest, to our foreign policy, we’ll revoke the visa.”

In the past, even when international students lost their entry visas, they were typically permitted to keep their legal residency, allowing them to stay and continue their studies but requiring them to reapply for a visa should they leave the country and wish to return.

In many instances the Trump administration has revoked both, opening students up to the possibility of arrest if they don’t depart.

“These are troubling times, and this situation is unlike any we have navigated before,” Minnesota State University in Makato President Edward Inch wrote in a Wednesday, April2, email, informing the campus that five international students had their visas revoked for reasons that were unclear.

Over the past two decades, as the number of college-age students in Michigan has dwindled, the state’s public universities have come to rely on significant numbers of international students, particularly undergraduates who typically pay more the double the tuition of their in-state counterparts.

At CMU, nearly 12% of the university’s 14,426 students are from a different country. At Michigan State University, it’s 9%. At the University of Michigan, it was more than 16% last fall.

“To our international students, faculty, and staff: You are welcome here, and we are glad to have you as members of our community,” MacKinnon and Lancaster wrote. “In uncertain times, we rely on our friends, colleagues, and neighbors to help us weather challenges.”