Washington (CNN) Democratic presidential candidate Bernie Sanders said Sunday that "the world has changed" and that American voters are now more concerned with a presidential candidate's positions than their gender or racial identity.

All candidates, Sanders added later during the interview with NH Public Radio, have "their own sets of problems" when running for public office. His comments cap off a tense six days between the Vermont senator and his progressive colleague, Massachusetts Sen. Elizabeth Warren, over gender, identity and presidential politics.

Warren said last Monday that Sanders told her during a private 2018 meeting that a woman could not win the presidency. In a CNN story published earlier that day, four sources had said Sanders had told Warren in the meeting a woman couldn't win. The claims touched off one of the most public feuds between the two candidates ahead of the Iowa caucuses.

"The world has changed. And to those people who think that a woman cannot be elected you're dead wrong. If you think a gay American cannot be elected you are dead wrong. If you think an African American cannot be elected you are dead wrong," Sanders said in the interview Sunday. "I think the American people have moved very significantly in trying to look at candidates based on what they stand for, not on their gender, not on their sexuality, not on their race."

Asked during the interview about the meeting he and Warren had before launching their White House bids last year, Sanders said he didn't "want to get into what was a private conversation," pivoting instead to say: "It is hard for me to imagine how anybody in the year 2020 could not believe that a woman could become president of the United States." Sanders reiterated that he had tried to draft Warren to launch a White House bid in 2016.

Responding to Sanders' interview, Warren told reporters later Sunday that she has "no further comment on this," adding: "I have been friends with Bernie for a long time. We work together on many, many issues. And I've said all I'm going to say on this topic."

'Their own set of problems'

During his radio interview, Sanders did agree there is an anxiety that exists around electing a woman to the presidency, but made the point that "as a country, we have come a long way," pointing to how the US grew to accept an African American as president, and has come a long way in terms of gay rights by accepting former mayor of South Bend, Indiana, Pete Buttigieg, another 2020 hopeful, as a "serious candidate" who is openly gay and married.

Asked if he believes woman candidates have a different experience running for president and if gender is still an obstacle for female politicians Sanders said: "Look, look I think, the answer is 'yes,' but I think everybody has their own sets of problems."

The senator then argued that just as Warren has to grapple with her gender and Buttigieg has to grapple with being thought of as too young, Sanders must face voters who think he is too old. In this context, Sanders referred to Warren being a woman as one of the negatives voters must consider. "Yeah, so everybody, you know, brings some negatives if you like," he said.

"There are a lot of people that said well, you know I like Bernie, he's a nice guy, but he is 78 years of age, alright? So we have to argue please look at the totality of who I am," he said.

"I would just hope very much that the American people look at the totality of a candidate, not at their gender, not at their sexuality, not at their age, but at everything."

After his town hall in Conway, New Hampshire, Sanders elaborated on his earlier remarks.

"I think anybody who doesn't understand that there is an enormous amount of sexism in this country. That there is homophobia in this country. That there is anti-Semitism in this country," Sanders told CNN. "That there is ageism in this country. That there is religious bigotry in this country and that you think that doesn't impact the political process, I think you would be mistaken."

A heated exchange

The candidates' feud came to a head immediately following the conclusion of the CNN/Des Moines Register Democratic presidential debate Wednesday when the two senators engaged in a heated and brief conversation in which they confronted one another about the differing accounts they shared during the debate. Sanders vehemently denied questioning whether a woman could win the presidency during the debate, while Warren called Sanders her "friend" and insisted she wasn't there "to try to fight with Bernie."

"I think you called me a liar on national TV," Warren can be heard saying after the debate to Sanders, who replied: "What?"

"I think you called me a liar on national TV," she repeated.

"You know, let's not do it right now. If you want to have that discussion, we'll have that discussion," Sanders said, to which Warren responded, "Anytime."

"You called me a liar," Sanders continued. "You told me -- all right, let's not do it now."