The Trump administration is trying to strip Harvard of its ability to enroll international students — an effort blocked by a federal judge on Friday, just hours after the university filed a lawsuit claiming Trump was violating its First Amendment rights.

Harvard University is challenging the Trump administration's decision to bar the Ivy League school from enrolling foreign students, calling it unconstitutional retaliation for defying the White House's political demands. It is the school's second suit against the Trump administration.

Fear and confusion mounted quickly on Thursday as international students, who make up more than a quarter of the university’s enrollment, sought clarity or reassurance.