President Donald Trump is moving to block nearly all foreign students from entering the country to attend Harvard University, his latest attempt to choke the Ivy League school from an international pipeline that accounts for a quarter of the student body.

President Donald Trump took direct action against Harvard University Wednesday night by issuing a proclamation barring the university's international students from entering the U.S. — a move Harvard called "illegal.

The move to limit student visas at Harvard comes days after a judge blocked the Trump administration’s attempts to revoke the school’s ability to host foreign students.