Since returning to the White House, Trump has targeted prestigious universities, alleging anti-Semitism and liberal bias -- with Harvard a primary quarry. 

He has launched what one academic called a "blitzkrieg" of measures -- arresting overseas students and researchers, slashing federal funding, and seeking to end Harvard's tax-exempt status.

"It's what they deserve!" Trump wrote on his Truth Social platform Friday. 

Unlike other universities that have bowed in recent days, Harvard defied Trump -- suing his administration and mounting a fightback praised by students, faculty and commentators. 

"This is not about scalping [Harvard]. This is about blitzkrieg and bringing out the biggest guns that you have," said Sheila Jasanoff, a Harvard Kennedy School professor, her bookcases overflowing with books and articles. 

"There's been essentially no check to the appetite of this administration." 

First-year student Feodora Douplitzky-Lunati said "there's a lot more wariness" among foreign students who fear they could be caught in immigration raids like those at Tufts and Columbia. 

Signs have advised international students not to discuss visa status, said Douplitzky-Lunati, who plans to study Slavic studies and economics.

Harvard researcher Kseniia Petrova has been detained since February, after her visa was revoked returning from France. 

Students involved in pro-Palestinian protests following the Oct. 7, 2023 attacks on Israel and the Gaza conflict have been arrested and slated for deportation at other campuses. 

Trump's team imposed an April 30 deadline for universities to hand over international student data or risk losing a key certification to sponsor international students -- affecting 27 percent of Harvard's student body. 

In an email seen by AFP, Harvard said it complied, but encouraged students to focus on their studies.

Read also: Trump says Harvard University's tax-exempt status will be revoked

"I'm very concerned for my peers, and I hope most of my friends are as well," said fourth-year US student Alice Goyer, sitting in a park near campus as students sipped coffee serenaded by a guitarist. 

"[We're] at the forefront of a political battle [...] And I think the international students especially have been caught in the crossfire -- they're kind of being used as bargaining tools," she said, accusing Trump of using an "authoritarian" playbook.

Students described growing anxiety. Many foreign students face the dilemma of leaving for summer break and risking being denied re-entry to the United States. 

'People are scared'

Alongside visa measures, Trump has targeted Harvard's finances. 

He put US$9 billion in federal funding under review, ultimately freezing $2.2 billion in grants and $60 million in contracts in an opening salvo.

Read also: Harvard sees $2.2 billion in funding frozen after defying Trump

Harvard imposed a hiring freeze, some researchers received stop-work orders, and its Chan School of Public Health was particularly exposed to the cuts.

"The administration have been much more aggressive than anyone anticipated. There's going to be chaos. The staff will get smaller," said one casualty of the cuts who suggested US HIV and tuberculosis cases would increase as a result.

In remarks to alumni shared with AFP, Harvard President Alan Garber said Wednesday the university's endowment cannot legally offset shortfalls caused by Trump. 

"It is an assault on higher education. We must join not only with the rest of the academic community, but with civil society," he said according to an alum on the call.

Another said Garber described the situation as a long, existential battle, and appealed for alumni donations. 

While Goyer said she was "very proud right now to be a Harvard student" because of its defiance, she acknowledged Harvard had yielded on some points. 

Harvard has said it would rename its diversity, equity and inclusion department -- which had drawn Trump's ire -- and defund graduation events held by affinity groups for Black, Latino, LGBTQ and other minority students. 

"I think it's related to the Trump demands," Goyer said. 

"It's still kind of bowing down to Trump." 

Leo Gerden, an economics and government student from Sweden, has defied the risks and become a visible international protester against Trump's policies. 

"People are scared, and I understand them," the 22-year-old said, citing the arrest by immigration officers of Rumeysa Ozturk at nearby Tufts, who wrote a pro-Palestinian op-ed. 

"Trump's strategy right now is to [make] an example out of a few people -- like Rumeysa -- to scare everyone else into silence.

"My hope is that by the end of this we're gonna see protests just as big as during the Vietnam War."