Donald Trump wanted to pit an all-black team of contestants against an all-white team to boost ratings on his NBC programme The Apprentice.

The president ran the idea for a racial divide on the fourth season of the reality show past radio shock jock Howard Stern, according to an unearthed 2005 interview.

“It would be nine blacks against nine whites, all highly educated, smart, strong, beautiful people, right? Do you like it?” he can be heard asking the host.

“Yes,” replied Mr Stern. “Do you like it?” Mr Trump asked African-American radio co-host Robin Quivers. “I think you’re going to have a riot,” she said.

Although Mr Stern suggested to Mr Trump that “on some level it’s wrong", the star and producer of the TV show insisted he could make it work.

“I think that it would be handled very beautifully by me," the future president said.

"Because, as you know, I’m very diplomatic.”

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NBC executives ultimately rejected the black versus white concept, with one saying, “I don’t think so,” according to The New York Times, which re-examined the whole incident after an audio clip of The Howard Stern Show interview resurfaced online.

It comes as the president receives more flak for subjecting four congresswomen of colour to a series of racist tweets. Mr Trump doubled-down on his attacks Sunday by claiming: “I don’t believed the four Congresswomen are capable of loving our Country.”

While some of Mr Trump’s African-American allies have attempted to defend him in recent days, other former associates – including ex-Apprentice stars – have spoken out.

“Let me be clear: Donald Trump is a disgusting, filthy, petty racist and he is trying to start a race war in this country and what we saw this week is just the beginning,” Omarosa Manigault Newman, a former contestant on The Apprentice who worked briefly at the White House, told The New York Times.

Randall Pinkett, who won the fourth season of the business-themed show before Mr Trump suggested he might like to share the prize with a white contestant, told the newspaper: “I would describe it as racist. Not even racist overtones – racist.”

Rep Elijah Cummings, the Democratic chairman of the House of Representatives Oversight Committee, denounced Mr Trump’s latest attacks on the so-called “squad” of liberal women in Congress by saying he had “no doubt” that the president was a racist.

“These are folks and women who love their country and they work very hard and they want to move us towards that more perfect union that our founding fathers talked about,” said Mr Cummings.