Sanders hammered the business mogul for being divisive and drumming up fears for political gain.
"I think creating and playing off the anxiety and the fears that the American people have, the fears about terrorism, the fears about our economy, and becoming a demagogue about that and then trying to get us to hate Mexicans or to hate Muslims -- I think that is a strategy that is not what America is supposed to be about," he said.
CNN host Chris Cuomo noted that Trump's popularity is "inarguable."
"I think it has to do with the fact that Trump is very smart," Sanders said. "He knows that media is not so interested in the serious issues facing this country. They love bombastic remarks, they love silly remarks. If he says that somebody is sweating that is a major story. ... And all that silly business, the personal attacks, that kind of works."
"I think this is more of an indictment of the media actually than it is of Trump," he added.
Sanders expressed optimism his campaign's own strategy will win out.
"I'm trying to bring people together to take on the wealthy and the powerful who have done so much to hurt the middle class. Trump is trying to play on fears and divide us up," he said. "At the end of the day, I believe that our approach will win."
HuffPost Pollster, which averages all publicly available polling data, places Trump leading Republican candidates at 38 percent, while Sanders is in second place behind Hillary Clinton, at 29.5 percent. See below.
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