WASHINGTON — President Donald Trump’s administration on Monday intensified its battle with Harvard University, formally finding the school tolerated antisemitism — a step that could jeopardize all of Harvard’s federal funding, including federal student aid.

In a letter sent to Harvard, a federal task force said its investigation had found the university was a “willful participant” in antisemitic harassment of Jewish students and faculty. The task force threatened to refer the case to the Justice Department to file a civil rights lawsuit “as soon as possible,” unless Harvard comes into compliance.

The finding escalates the White House’s conflict with Harvard, which has faced mounting sanctions after rejecting a list of federal demands calling for sweeping changes to campus governance, hiring and admissions. Already, the government has slashed more than $2.6 billion in research grants. But the civil rights violation could jeopardize Harvard’s eligibility to accept federal loans or grants for students to attend the university — a penalty often referred to as a “death sentence” in higher education.

“Failure to institute adequate changes immediately will result in the loss of all federal financial resources and continue to affect Harvard’s relationship with the federal government,” officials said in the letter, which was obtained by The Associated Press and first reported by The Wall Street Journal.

The Trump administration for months has accused Harvard of tolerating antisemitism on its campus, but a formal investigative finding gives the administration a channel to block more federal funding.

Trump personally has railed against Harvard, but on June 20 suggested a deal resolving the monthslong conflict could be coming soon. In a post on social media, Trump said Harvard has “acted extremely appropriately” during negotiations. He did not elaborate on the terms of a potential resolution.

Harvard has not commented on whether it is negotiating with the White House. On Monday, Harvard said it strongly disagrees with the government’s findings and is committed to fighting bias.