The Trump administration has threatened to block Harvard University from enrolling international students unless the school hands over detailed information about the student body, in yet another escalation of the government’s fight against higher education.

In a letter sent on Wednesday, Kristi Noem, the homeland security secretary, demanded “relevant information” regarding each student visa holder at Harvard who has been involved with “known illegal” or “dangerous” activity.

She also demanded information “regarding each student visa holder’s maintenance of at least the minimum required coursework to maintain nonimmigrant student status.”

“The failure to comply with the student records request will be treated as a voluntary withdrawal,” Ms. Noem wrote in the letter, which was obtained by The New York Times.

The letter was sent after Harvard refused President Trump’s demands to make sweeping changes to its policies on admissions and hiring. The White House hit back with a series of financial threats and penalties.

Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.

Thank you for your patience while we verify access.

Already a subscriber? Log in.

Want all of The Times? Subscribe.