The US justice department has accused Yale University of illegally discriminating against Asian-American and white applicants in its undergraduate admissions process in violation of US civil rights law.

The findings are the result of a two-year investigation in response to a complaint by Asian-American groups concerning Yale’s conduct, the department said in a statement on Thursday.

The department said it was prepared to file a lawsuit against Yale if the school, in New Haven, Connecticut, did not take “remedial measures”.

A Yale spokeswoman said the university “categorically denies” the allegations but has cooperated fully with the investigation.

The justice department made its findings before allowing Yale to provide requested documents, Yale said.

“Had the department fully received and fairly weighed this information, it would have concluded that Yale’s practices absolutely comply with decades of Supreme Court precedent,” the spokeswoman said.

The justice department said that although race can lawfully be considered in college admissions in limited circumstances, “Yale’s use of race is anything but limited”.

The elite school “uses race at multiple steps of its admissions process resulting in a multiplied effect of race on an applicant’s likelihood of admission”, the justice department said.

The justice department has previously filed legal briefs in support of a lawsuit, brought by affirmative action opponents, accusing Harvard University of discriminating against Asian Americans.

A federal judge in Boston ruled in favour of Harvard last year, saying the school’s affirmative action programme advanced a legitimate interest in having a diverse student body.

An appeal of that ruling is pending. The case could eventually reach the Supreme Court.

Affirmative action programmes in higher education were meant to address racial discrimination.

The Supreme Court has ruled universities may use affirmative action with the aim of helping minority applicants get into college.

US conservatives have said that in helping Black and Latino applicants, affirmative action can hurt white people and Asian Americans