As colleges around the country are reporting cases of international students suddenly learning their visas have been revoked, Penn State University is urging international students, scholars and faculty to carry with them at all times copies of their proof of legal status in the United States.

In addition, the university said when Penn State Global becomes aware that a student has had their lawful status in the U.S. terminated, a staff member will reach out directly to the student to make them aware of the situation.

According to a letter emailed to the Penn State community on April 3, Sabine Klahr, interim vice provost of Penn State Global, said the university is aware of incidents that have occurred around the country where some international students have had their lawful status in the United States terminated.

The university did not state how many Penn State students had their legal status terminated, but said Penn State is “closely monitoring any potential changes that could affect our international community.”

“We want to remind you of the guidance and resources that are currently available to you while we continue to monitor evolving federal actions and policies related to immigration and international travel, particularly as they pertain to the Penn State community,” Klahr said in the letter.

While visas can be canceled for a number of reasons, college leaders say the government has been quietly terminating students’ legal residency status with little notice to students or schools. The move leaves students vulnerable to detention and deportation.

A growing list of colleges that have announced discovering students with revoked status recently includes Harvard, Stanford, Michigan, UCLA and Ohio State University.

The Trump administration has targeted students who had been involved with pro-Palestinian activism or speech, with a few high-profile detentions of students including Mahmoud Khalil, a green card holder who was a leader of protests at Columbia University.

But more schools are seeing visas stripped from students with no known connection to protests. In some cases, past infractions such as traffic violations have been cited. Some colleges say the reasons remain unclear to them — and they are seeking answers.

“What you’re seeing happening with international students is really a piece of the much greater scrutiny that the Trump administration is bringing to bear on immigrants of all different categories,” said Michelle Mittelstadt, director of public affairs at the Migration Policy Institute.

International Student & Scholar Advising in Penn State Global recommends international students, scholars and faculty keep documentation regarding their visa status up-to-date and always carry copies of proof of status, such as a photocopy or scan/digital copy of their primary immigration documents. ISSA provides guidance, which is updated periodically, about which documents should be carried based on visa type.

Students on F-1 or J-1 student visa status should carry their main passport page, current I-94 Record, their most recent I-20/DS-2019 and their most recent visa. The university also recommends students carry their class schedule and a copy of the Immigration Lawyers Association’s “Know Your Rights” document.

The university stated that anyone approached by ICE or other federal law enforcement officers on campus should alert the University Police, remain calm and ask for the officer’s identification. If an officer provides identification and a signed warrant, students, scholars and faculty must comply with their orders, but the university reminded those who may be taken into custody that they have the right to remain silent. The university also urged bystanders to not interfere with federal law enforcement officers.

Penn State issued warnings about travel plans, stating that those making international travel plans should use caution as rules regarding travel “may change suddenly and without warning.”

Those traveling within the United States — driving on major highways, riding on buses, trains or planes — should also carry their key documents showing their legal status in the U.S., the university said.

The university said those on a visa sponsored by Penn State can reach out to the International Student & Scholar Advising. Those who are in the U.S. but not on a Penn State-sponsored visa, and those with specific questions or concerns about their immigration status, are urged to contact an immigration attorney.

In the letter, Klahr said, “We understand that uncertainty can be stressful, and we genuinely care about your well-being. We encourage you to take care of yourself and make use of the many campus resources available to support your mental and personal health during this time.”