The Trump administration on Thursday halted Harvard University’s ability to enroll international students, a major escalation in the administration’s efforts to pressure the college to fall in line with the president’s agenda.

The administration notified Harvard about the decision after a back-and-forth in recent days over the legality of a sprawling records request as part of the Department of Homeland Security’s investigation, according to three people with knowledge of the negotiations.

“I am writing to inform you that effective immediately, Harvard University’s Student and Exchange Visitor Program certification is revoked,” according to a letter sent to the university by Kristi Noem, the homeland security secretary. A copy of the letter was obtained by The New York Times.

Spokespeople for the Department of Homeland Security and Harvard did not immediately respond to requests for comment.

(New York Times news service)