Washington | A federal judge late Thursday temporarily blocked a proclamation by President Donald Trump that banned foreign students from entering the US to attend Harvard University.

Trump's proclamation, issued Wednesday, marked the latest attempt by his administration to cut off the nation's oldest and wealthiest college from a quarter of its student body, which accounts for much of Harvard's research and scholarship.

Harvard filed a legal challenge the next day, asking for a judge to block Trump's order and calling it illegal retaliation for Harvard's rejection of White House demands. Harvard said the president was attempting an end-run around a previous court order.

A few hours later, US District Judge Allison Burroughs in Boston issued a temporary restraining order against Trump's Wednesday proclamation. Harvard, she said, had demonstrated it would sustain “immediate and irreparable injury” before she would have an opportunity to hear from the parties in the lawsuit.

Burroughs also extended the temporary hold she placed on the administration's previous attempt to end Harvard's enrollment of international students. Last month, the Department of Homeland Security revoked Harvard's certification to host foreign students and issue paperwork to them for their visas, only to have Burroughs block the action temporarily. Trump's order this week invoked a different legal authority.

If Trump's measure survives this court challenge, it would block thousands of students who are scheduled to come to Harvard's campus in Cambridge, Massachusetts, for the summer and fall terms.

“Harvard's more than 7,000 F-1 and J-1 visa holders - and their dependents - have become pawns in the government's escalating campaign of retaliation,” Harvard wrote Thursday.

While the court case proceeds, Harvard is making contingency plans so students and visiting scholars can continue their work at the university, President Alan Garber said in a message to the campus and alumni.

“Each of us is part of a truly global university community,” Garber said Thursday. “We know that the benefits of bringing talented people together from around the world are unique and irreplaceable.”