Harvard University has filed a lawsuit against President Donald Trump’s latest directive to bar foreign students from entering the US, calling it “illegal retaliation” for the university’s rejection of White House demands. The lawsuit comes after Trump signed a proclamation suspending the entry of foreign nationals seeking to study or participate in exchange programs at Harvard University.

According to the proclamation, Trump cited concerns about Harvard’s ties to foreign governments, particularly China, and its handling of student misconduct records. The university allegedly received over $150 million from China and failed to provide sufficient information about foreign students’ misconduct.

Harvard argues that Trump’s action is an attempt to circumvent a previous court order and that targeting only Harvard students doesn’t qualify as a “class of aliens” under federal law. “The President’s actions thus are not undertaken to protect the ‘interests of the United States,’ but instead to pursue a government vendetta against Harvard,” the university wrote in its filing.

US District Judge Allison Burroughs issued a temporary restraining order against Trump’s proclamation, saying Harvard had demonstrated “it will sustain immediate and irreparable injury before there is an opportunity to hear from all parties.”

The uncertainty has left international students like Yonas Nuguse, a 21-year-old student from Ethiopia, anxiously waiting to find out if he’ll be able to attend Harvard. Nuguse was granted a visa to study at Harvard and worries it might be too late to reverse his decision and attend another university.

“I hope the situation is temporary and I can enroll on time to go on and realize my dream far from reality in Ethiopia,” Nuguse said. Harvard President Alan Garber said the university is making contingency plans to ensure students and visiting scholars can continue their work.

The standoff comes as the Trump administration tightens scrutiny of student visas nationwide. Thousands of students lost permission to be in the US this spring before the administration reversed itself. Secretary of State Marco Rubio announced the US would “aggressively revoke” visas for students from China.

International student interest in the US has dropped significantly, according to Mike Henniger, CEO of Illume Student Advisory Services. “It is one blow after another,” Henniger said. “At this point, international student interest in the US has basically dropped to nil.”

Craig Riggs, editor of ICEF Monitor, urges families to consult carefully with advisers and not overreact to the headlines. “The rules under which students would make this huge decision to devote years of their lives and quite a bit of money to studying at Harvard have been shown to change quite quickly,” Riggs said.