A group of contestants on Donald Trump's former reality television show "The Apprentice" put their old boss in the hot seat on Friday, saying the U.S. Republican front-runner had widened racial divisions and should not be president.

Trump's one-time admirers, most from racial minorities, urged the New York billionaire to tamp down his divisive rhetoric as he campaigns to succeed Democratic President Barack Obama in a Nov. 8 election.

"We are all disappointed and in some ways shocked to see what is being spewed from Donald regarding his views on women, immigrants, and the list goes on," said Randal Pinkett, winner of the 2005 fourth season of the reality television show.

"We strongly condemn Donald's campaign of sexism, xenophobia, racism, violence, and hate," he said at a news conference in Manhattan.

Running for 14 seasons, "The Apprentice" gave Trump a national platform. His often blunt and unfiltered style helped make the show a major hit. The show featured groups of business-minded contestants vying for a titular apprenticeship in Trump's organization. At its peak, nearly 21 million people watched the show.

Pinkett cited private conversations, time spent off-screen and images projected from the billionaire businessman's blustery rise to the top of the Republican heap as evidence that Trump "is not worthy of the highest office of the land."

Trump's proposals to ban Muslims and build a wall at the Mexican border have drawn criticism even within his party. His campaign has been accused of tacitly encouraging violence at large and rowdy rallies where Trump supporters have at times clashed with protesters.

Pinkett told Reuters he had contacted former "apprentices" and said their effort was independent and timed to precede a crucial nominating contest on Tuesday in New York.

It seemed unlikely their effort would dent Trump's comfortable advantage in New York opinion polls against rivals Ohio Governor John Kasich and U.S. Senator Ted Cruz of Texas.