Harvard University’s lawyers responded on Monday to the Trump Administration’s letter demanding a series of policy changes, saying the demands were unlawful and that Harvard would not comply.

The president of Harvard on Wednesday defended the university’s decision to sue the Trump administration, adding that the institution “cannot compromise” on core principles like the First Amendment. Harvard took legal action against the Trump administration on Monday over the government’s decision to freeze over $2 billion in federal funding meant for the university after it refused to make the reforms it ordered.

Harvard University sued the Trump administration Monday in a new escalation of the fight over institutional oversight, independence and federal funding for the Ivy League school.