The Trump administration has moved to end Harvard’s ability to enrol international students, escalating a standoff with America’s oldest university.

Homeland Security Secretary Kristi Noem wrote on X that the administration had revoked Harvard’s “Student and Exchange Visitor Program certification as a result of their failure to adhere to the law.”

She also wrote, “Let this serve as a warning to all universities and academic institutions across the country.”

Harvard called the move “unlawful” in a statement.

It adds, “We are fully committed to maintaining Harvard’s ability to host our international students and scholars, who hail from more than 140 countries and enrich the University – and this nation – immeasurably. We are working quickly to provide guidance and support to members of our community. This retaliatory action threatens serious harm to the Harvard community and our country, and undermines Harvard’s academic and research mission.”

Nearly 7,000 international students were enrolled at the institution last academic year, university data shows, making up 27% of its student body.

In recent months, the White House demanded that Harvard make changes to hiring, admissions and teaching practices to help fight antisemitism on campus.

Harvard however said it had taken many steps to address antisemitism, and that the demands from the Government were an effort to regulate the university’s “intellectual conditions”.