CHICAGO (WLS) — More than 18,000 international students occupy the classrooms of University of Illinois campuses across the state, each with an approved visa that allows them to legally study in the United States.

But those visas are becoming increasingly endangered.

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An international student at Southern Illinois University is now in immigration limbo because their student visa was abruptly revoked late last week.

That prompted the school to circulate a letter to students “reassuring support” and encouraging international students to take precautions including carrying copies of immigration documents, proof of enrollment at SIU, and records of all U.S. residences.

The university wouldn’t elaborate on the reason for the revocation or the student’s country of origin.

Just two days prior video showed ICE agents surrounding and detaining a Turkish student at Tufts University on the street in suburban Boston. She’s now one of at least seven students or professors targeted for removal by Immigrations and Customs Enforcement, but not one has been charged with a crime.

According to Secretary of State Marco Rubio, the Trump administration has revoked roughly 300 student visas and counting. It’s a triggering reality for University of Illinois Chicago’s heavily international student population.

“I’m nervous because my visa is going to be expired soon,” UIC freshman Connie Kim told the I-Team. Kim is from Korea.

On their first day back from spring break, some international students are grappling with how to safely travel.

“My friends are afraid of going back to their hometowns because they’re afraid they might not come back through visa control,” said UIC freshman Beka Seidrassyl, who is from Kazakhstan.

UIC didn’t comment on the I-Team’s questions about university policies to protect international students and staff.

“There are a lot of international students on campus. So, it’s their duty to make us feel safe and they do it very well,” said UIC sophomore, Neel Nanavati, who is from India.

In a statement, administrators at University of Illinois Urbana-Champaign told the I-Team, “Our International Student and Scholar Services team stays in close contact with our international students. They also have a blog that shares new information as we learn more about the ramifications of changes at the federal level.”

With college campuses now in immigration crosshairs, some international students are questioning the safety of their academic future.

“Just in a month, summer break is coming, and a lot of people are planning to go back. They are concerned, lot of people are planning to go back,” Nanavati told the I-Team.

Secretary of State Rubio recently said he revokes students visas every day for people that the administration says are connected to certain student protests activities including vandalism, and writing op-eds.

According to federal data, more than one million people are in the United States studying on student visas this school year.