The U.S. Justice Department has threatened to sue Harvard University to obtain a trove of records as part of an investigation into the university’s admissions practices following a lawsuit from a group of Asian-American students.

A Nov. 17 letter from the department gives Harvard until Dec. 1 to turn over a variety of records that Justice officials requested in September, including applications for admission and evaluations of students.

The department said Harvard has pursued a "strategy of delay" and threatened to sue if it doesn’t meet the department’s deadline.

"We sincerely hope that Harvard will quickly correct its noncompliance and return to a collaborative approach," the letter said, adding that "Harvard has not yet produced a single document."

The inquiry is related to a federal lawsuit filed by a group of students in 2014 alleging Harvard limits the number of Asian Americans it admits each year. A similar complaint was made to the Justice Department.

A statement from Harvard on Tuesday said it will "certainly comply with its obligations" but also needs to protect confidential records related to students and applicants.

The university said it has been "seeking to engage the Department of Justice in the best means of doing so."