NEW YORK, June 6, 2025 (BSS/AFP) - Donald Trump's late night proclamation blocking Harvard's new international students has sparked fear and anger among existing students left in limbo amid the escalating showdown between the US president and their university.

Alfred Williamson, a Welsh-Danish physics and government student in his second year at Harvard, said he was "clinging onto the hope that Harvard will win this fight and that I will get to return next semester."

Harvard had won a reprieve from a judge who paused an earlier bid by Trump to revoke the university's ability to sponsor the school's large international student population -- 27 percent of the total.

"Then the Trump administration does whatever it can to crush those dreams," Williamson, 20, told AFP of Trump's proclamation Wednesday alleging that "Harvard's conduct has rendered it an unsuitable destination for foreign students and researchers" and also threatened existing international students with visa cancellations.

"This represents another authoritarian instance of executive overreach, which punishes international students for attending a university that refuses to bow down to the administration," said Williamson who is vacationing outside the United States.

He said "Trump is targeting Harvard because it has the integrity to stand up to his unlawful and un-American demands."

Harvard has been at the forefront of Trump's campaign against top universities after it defied his calls to submit to oversight of its curriculum, staffing, student recruitment and "viewpoint diversity."

The government already cut around $3.2 billion of federal grants and contracts benefiting Harvard and pledged to exclude the Cambridge, Massachusetts, institution from any future federal funding while threatening its tax-exempt status.

- 'Campaign of retaliation' -

On Thursday, Harvard added the latest measure to legal action against the Trump administration, arguing in a court filing that "this is not the Administration's first attempt to sever Harvard from its international students." It called it part of a "campaign of retaliation."

A graduate student at the Harvard Kennedy School of Government from India who declined to be named said: "I just read this latest news. We have not received anything from Harvard yet, but this isn't surprising -- albeit concerning."

"I knew it was going to be a long summer."

One international student who declined to be named for fear of retribution raised the plight of international students who had moved their lives to Harvard, leaving for the summer break, and now faced uncertainty following Trump's order.

"What about students who went home for the summer? There's a risk they won't be able to come back," said the student who is currently seeking to renew their own visa.

Legal experts said Harvard would need to explore a range of options to protect its foreign students alongside the legal action.

"(They) need to act quickly on an administrative level to explore options for its international student population which could possibly include program deferrals, transitions to online instruction, or other alternatives to ensure academic continuity," said attorney Khensani Mathebula, who works with the Laura Devine Immigration firm.

"Staying informed and proactive is essential in protecting (students') academic and immigration status."

A US Harvard student of government going into her fourth year who is friends with many international students, Olivia Data, said "this news is heartbreaking and scary."

"Our friends and classmates are being used as collateral in a dictator's grab for power, and none of us know where it will end or whether our university can protect its students in our current political system," she said.