"The truth is that for a campaign that started out as a fringe campaign at 3% in the polls we have enormous momentum," Sanders told CNN's Jake Tapper on Sunday's "State of the Union." "You have noticed that one of the recent national polls actually had us ahead of Hillary Clinton, in state after state her margin is narrowing. So I think people are responding to our message of a rigged economy where ordinary Americans work longer hours for lower wages and almost all new income goes to the top one percent."
Sanders lost Nevada by about five percentage points. he played up his success among Latino voters in Nevada, but acknowledged he need to do better among black voters.
"I believe we won the Latino vote, which is a huge, huge way forward for us. We did badly with the African-American vote," Sanders said.
Lack of support from African-American voters will be a concern for Sanders heading into next Saturday's South Carolina primary where black voters make a up a large percentage of the Democratic electorate.
"I think the more the African-American community hears our message on a broken criminal justice system -- which has more people in jail today than any country on earth, largely African-American and Latino -- when they hear our message of an economy that represents all of us, not just the 1%. I think you're going to see us making progress there as well," Sanders said.
Sanders blamed his Nevada loss on a lack of turnout.
"I wish we had had a larger voter turnout," Sanders said Sunday on NBC's "Meet the Press." "We did phenomenally well with young people. I think we did well with working class people. But remember, we were taking on a candidate who ran in 2008. She knew Nevada a lot better than we did, she had the names of a lot of her supporters."
Despite coming off a loss, Sanders downplayed talk that he was only running to push a populist economic message. Clinton, who used increasingly tough rhetoric against Wall Street and banks, cited her preparation to take them on during her victory speech Saturday.
"We're looking into the copyright issues here. Those are our words," Sanders joked on NBC. "Well, obviously, I think what the secretary has recognized is the American people are extremely angry about the power of Wall Street, the greed, the illegal behavior of Wall Street."
Sanders also commented Sunday on a recently unearthed photo of him being arrested in 1963, during a protest in Chicago.
"It was an interesting day," he said on CNN, adding that he recalled protesting segregated schools and being thrown in a police wagon.
The Sanders campaign has played up the photo, taken by The Chicago Tribune
, as evidence of his Civil Rights bona fides.