More than a dozen Republican state prosecutors have threatened the top 100 US companies with legal action over workforce diversity programmes.

They warned corporate targets like "race-based quotas" may be unlawful after the Supreme Court banned colleges using affirmative action in admissions.

The Republican attorneys general name firms like Apple, Microsoft and Uber.

They say "treating people differently because of the color of their skin, even for benign purposes, is unlawful".

Tennessee Attorney General Jonathan Skrmetti and Kansas Attorney General Kris Kobach led the effort and signed the letter alongside 11 other attorneys general.

Among the other Fortune 100 companies named in the letter are the likes of Facebook, Airbnb, Paypal, Google, Netflix and Uber.

In a statement shared with the BBC, Mr Skrmetti said "the [Supreme] Court's reasoning means that companies, no matter their motivation, cannot treat people differently based on the color of their skin. 

"Corporate America continues to have many avenues to help disadvantaged people and communities of all races without resorting to crude racial line-drawing."

The group is pointing to the Supreme Court's landmark ruling that Harvard and other US colleges could no longer consider race as a factor in admissions decisions.

Last month, the nation's highest court voted 6-3 to repeal affirmative action, also known as positive discrimination, a decades-old measure in the United States.

At the time, Charlotte A Burrows, who was appointed chair of the Equal Employment Opportunity Commission by US President Joe Biden, said the ruling "does not address employer efforts to foster diverse and inclusive workforces or to engage the talents of all qualified workers, regardless of their background".

But some experts had already predicted the ruling would concern legal counsels at corporations.

Alvin B Tillery Jr., director of the Center for the Study of Diversity and Democracy at Northwestern University, told the BBC he worries "there will be a chilling effect because of this letter".

He also said there would be repercussions for any companies who roll back diversity policies.

"Young people and young people of colour will punish companies who do not keep these programmes in place, as will their own employees, so this won't be as easy as the college admissions case was," he said.

Mr Tillery Jr cited last year's employee walkout at Disney amid the company's silence over a Florida sex education bill as an example of internal pressures corporations can face.

But the president of Students for Fair Admissions, Edward Blum, a legal activist who filed the affirmative action case, welcomed the letter from Republican officials.

He told the BBC: "It is long overdue for these practices to be challenged by our nation's legal authorities."

The BBC has reached out to the companies named in the letter for comment.