Winning admission to Harvard University fulfilled a longtime goal for Yonas Nuguse, a student in Ethiopia who endured a war in the country’s Tigray region, internet and phone shutdowns, and the pandemic — all of which made it impossible to finish high school on time.

Now, it’s unclear if he will make it this fall to the Ivy League campus in Cambridge, Mass.

He and other admitted students around the world anxiously are tracking the school’s feud with the Trump administration, which is seeking to keep it from enrolling international students.

On Thursday, Harvard challenged President Donald Trump’s latest move to bar foreign students from entering the U.S. to attend the college, calling it illegal retaliation for Harvard’s rejection of White House demands. In an amended lawsuit filed Thursday, Harvard said the president was attempting an end-run around a previous court order.

Last month, a federal judge blocked the Department of Homeland Security from revoking Harvard’s certification to host foreign students.

Increasingly, the nation’s oldest and best-known university has attracted some of the brightest minds from around the world, with international students accounting for one-quarter of its enrollment. As Harvard’s fight with the administration plays out, foreign students can only wait to find out if they’ll be able to attend the school at all. Some are weighing other options.

For Nuguse, 21, the war in Ethiopia forced schools to close in many parts of the province. After schooling resumed, he then took a gap year to study and save money to pay for his TOEFL English proficiency test in Addis Ababa, Ethiopia’s capital.

“The war affected me a great deal, and when I found out the news that I was accepted to Harvard, I was ecstatic. I knew it was a proud moment for my family, teachers, mentors and friends, who were instrumental in my achievement,” he said.

The following months have been filled with uncertainty. On Wednesday, Trump signed a directive seeking to block U.S. entry for Harvard’s international students, which would block thousands of students who are scheduled to head to Cambridge for summer and fall terms.

Harvard’s court challenge a day later attacked Trump’s legal justification for the action — a federal law allowing him to block a “class of aliens” deemed detrimental to the nation’s interests.

Targeting only those who are coming to the U.S. to study at Harvard doesn’t qualify as a “class of aliens,” Harvard said in its filing.

“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.

The standoff with Harvard comes as the administration has been tightening scrutiny of student visas nationwide. Thousands of students around the country abruptly lost permission to be in the U.S. this spring before the administration reversed itself, and Secretary of State Marco Rubio announced last week the U.S. would “aggressively revoke” visas for students from China.

“It is one blow after another,” said Mike Henniger, CEO of Illume Student Advisory Services, who works with colleges in the U.S., Canada and Europe to recruit international students. “At this point, international student interest in the U.S. has basically dropped to nil.”