Audio has been released of Donald Trump’s pick for secretary of Health and Human Services, Robert F Kennedy Jr, comparing the president-elect to Hitler and suggesting some of his supporters were “outright Nazis” and “bootlickers”.

Clips were uncovered by CNN from Kennedy’s radio show “Ring of Fire”, when in 2016 the anti-vaccine activist applauded descriptions of Trump’s base as “belligerent idiots” in addition to the Nazi comments.

After Trump won the 2016 US election, Kennedy concluded in one episode from December of that year that Trump was at least in one way not like Adolf Hitler, because, “Hitler was interested in policy.”

Trump was also compared to historical demagogues like Hitler and Benito Mussolini, as Kennedy accused him of exploiting societal insecurities and xenophobia to amass power.

In another episode, RFK Jr accused the former president of racism “in every statement he makes.”, CNN reported. It said he explained: “You know, we have to be fear of the Muslims. We have to be fear of the black people, and particularly the big Black guy Obama.”

“And only one person has the genius and the capacity to solve these things. And I’m not gonna tell you how I’m gonna do it. Just trust in me, vote for me and everything will be great again. And of course, that whole thing is like a carnival barker,” Kennedy concluded.

Comments from the show were among a string of attacks Kennedy has levelled at Trump as the pair have exchange criticism of one another over the years.

Kennedy this year accused Trump of betraying his followers, while Trump described Kennedy as “the most radical left candidate in the race.”

The former Democrat has now expressed remorse over previous comments, demonstrating support for Trump’s vision for the country.

“Like many Americans, I allowed myself to believe the mainstream media’s distorted, dystopian portrait of President Trump. I no longer hold this belief and now regret having made those statements,” he said in a statement to CNN.

An approval of Trump’s appointment would mean Kennedy would be in charge of the country’s top health agency.

The HHS oversees many of the US’ biggest health programmes and schemes including the Food and Drug Administration, the Centers for Disease Control and the massive Medicare and Medicaid Services programs, which provide health coverage for the poor, those aged 65 and older, and the disabled.

Trump said in a post on social media last week: “The Safety and Health of all Americans is the most important role of any Administration, and HHS will play a big role in helping ensure that everybody will be protected from harmful chemicals, pollutants, pesticides, pharmaceutical products, and food additives that have contributed to the overwhelming Health Crisis in this Country.”

Trump later praised Kennedy at his Mar-a-Lago home in Florida, saying he would do “unbelievable” things in his new position. “We want you to come up with things and ideas and what you’ve been talking about for a long time,” he said, without elaborating.

Kennedy ran for president in this year’s election as an independent before dropping out in August and endorsing Trump. He has since refrained from public criticism of him.

He repeatedly accused Trump of exploiting fear, bigotry and xenophobia to build a “dangerous” nationalist movement and warned Trump would destroy both the climate and clean water. Kennedy also compared Trump’s supporters to white Americans in the 1970s who, he said, viewed the Civil Rights Movement as a “social demotion.”