According to the Associated Press, over the past few weeks the Donald Trump administration has revoked the visas or legal status of more than 1,000 international students, both undergraduate and graduate.

Some were involved in protests over the Israeli-Palestinian conflict. The rationale for canceling the visas of many others remains unclear. Colleges across the country say that often they receive no warning from the federal government before a visa is revoked.

Over 1 million international students studied in the U.S. last year. After earning their degree, many international students enter the U.S. labor force, filling high-demand jobs in technology, business and engineering.

Outside International House, the dormitory for international students at the University of California, Berkeley, you could feel some of the anxiety. At least 23 of the university’s international students have had their legal status revoked.

It was hard to get anyone to talk. An American stranger asking foreign students where they’re from and what they’re studying — nowadays that raises eyebrows. One Chinese student asked if I was actually an undercover agent from the Immigration and Customs Enforcement agency.

One current international student agreed to an interview. We’re not using his real name or where he’s from.

”You know, with all of these people disappearing and all of that jazz, like, if I say something bad, it feels like, in this country, like if you criticize the government, you disappear as a guest,” he said. “So I wouldn’t want my name to be on it.”

He’s getting his Ph.D. in chemistry. And because Berkeley has the No. 1 chemistry graduate program in the country, once he’s done he’ll likely get plenty of lucrative offers from big American biotech companies.

But he’s not sure he wants to stay in the U.S. That’s partly because he just prefers home, but also because he’s not sure how welcome he is here.

”When you see an administration doing what they're doing, and it's like, yeah, then it's like I'm not interested. If you don't want me here, then I don't want to be here,” he said.

Hany Farid, a UC Berkeley computer science and School of Information professor, worries about the chilling effect the visa cancellations may have on future international enrollment, especially in science and engineering.

“What we are doing in this country now is going to be a generational-long impact,” said Farid. “You are creating a multi-multi-multi-year impact on science and discovery and innovation that will cripple the U.S. 10 years, 20 years, 30 years down the line.”

According to the National Science Board, student visa holders earn more than half of the Ph.D.s in computer science, engineering, math and statistics at U.S. universities. 

Farid specializes in digital forensics. His graduate students work on technology to tell whether an image or video has been manipulated with artificial intelligence.

He said most of the graduate students he’s worked with come from abroad, and after completing the program, most work in the U.S. In the past, they would commonly be hired by the U.S. government.

“So now, under this administration, why would anybody go look at the government? I certainly wouldn't recommend it,” said Farid. “The appetite will be zero.”

The Trump administration has said it is targeting international students who have disrupted universities during protests or engaged in illegal activity.

“No one’s entitled to a student visa,” Secretary of State Marco Rubio said this month at a press briefing after a Cabinet meeting. “The press covers student visas like they're some sort of birthright. No. A student visa’s like me inviting you into my home. If you come into my home and put all types of crap on my couch, I’m going to kick you out of my house.”

Multiple lawsuits have been filed against the administration on behalf of affected international students, citing a lack of due process.

Back at UC Berkeley’s International House, that Ph.D. chemistry student said that beyond the visa cancellations, the U.S. just makes it tough for high-skilled immigrants to stay here and work.

“It's very funny, right?” he said. “Because inherently, America is built on migration. A lot of the people who have come here and changed the game weren't American beforehand. So why are we making it difficult for people to stay? 

He said the money he might make in the U.S. will be hard to turn down. But he’s interested in how much Canadian companies would offer.