Washington DC - The US Supreme Court has dealt a blow to university affirmative action programs in the conservative majority's latest ruling.

The Supreme Court issued a ruling severely limiting the consideration of race in college admissions, striking down affirmative action programs after almost 40 years of legal precedent.

At issue were two separate lawsuits, launched in 2014 by conservative legal strategist Edward Blum's Students for Fair Admissions, over admissions policies at the University of North Carolina at Chapel Hill and Harvard University.

The Supreme Court agreed to hear the challenges in January, despite ruling in several prior cases that universities could consider race in admissions.

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On Thursday, the justices ruled 6-3 in the UNC case and 6-2 in the Harvard University case that race-conscious admissions policies violate the US Constitution's Equal Protection Clause. Justice Ketanji Brown Jackson was recused from the latter case, as she had served on Harvard's Board of Overseers until last spring.

"The student must be treated based on his or her experiences as an individual – not on the basis of race," Chief Justice John Roberts wrote in the majority opinion.

Proponents of affirmative action have long argued that such policies are crucial to ensuring diversity on college and university campuses and expanding access to higher education for underrepresented communities.

"Today, this Court stands in the way and rolls back decades of precedent and momentous progress," liberal Justice Sonia Sotomayor wrote in dissent. "It holds that race can no longer be used in a limited way in college admissions to achieve such critical benefits. In so holding, the Court cements a superficial rule of colorblindness as a constitutional principle in an endemically segregated society where race has always mattered and continues to matter."

President Joe Biden had urged the court to uphold Harvard and UNC's affirmative action policies before the decision was announced.