Democratic presidential candidate Bernie Sanders said it's "very unfortunate" a rule change could allow his fellow presidential candidate Mike Bloomberg into the next Democratic debates. The qualifications no longer include a unique-donor threshold.

"That is what being a multi-billionaire is about. Some very good friends of mine who were competing in the Democratic nomination — people like Cory Booker of New Jersey, Julián Castro — work really, really hard. Nobody changed the rules to get them in the debate," he said on "CBS This Morning" Friday.

"But I guess if you're worth $60 billion, you can change the rules. I think that is very, very unfortunate," he added.

Sanders has been critical of Bloomberg using his wealth to run for president since he entered the race.

When asked to respond to a recent Quinnipiac University poll with black voters that put Bloomberg and former Vice President Joe Biden ahead of him, Sanders expressed confidence in his support from minority communities.

"I don't know what the most recent poll has, but we are doing very, very well with minority communities, both African-American and Latino," he said.

"A lot of politicians go from the top on down. That's what Bloomberg is about. He's spending hundreds of millions of dollars. That's fine, we don't have hundreds of millions of dollars. Our movement is made up of working people, of young people, and we're going to put that coalition together, we are going to take on the establishment and I believe we're going to win."

Sanders also addressed the criticism from a Democratic congressman in South Carolina who recently said, "South Carolinians don't want socialism" in explaining why he doesn't support Sanders.

"In my view, to a significant degree, we are living, right now under Donald Trump, in a socialist society. The only difference is does the government work for working people or does it work for billionaires?" he said, explaining that he views tax breaks and subsidies for corporations and billionaires as "socialism for the rich."

Sanders, an Independent senator from Vermont, has long identified as a Democratic socialist. Pressed if that label is confusing voters and allowing his critics to hurt him politically, he said, "I'm not worried about labels. We will define ourselves, not let other people define us."

The next Democratic debate is Wednesday, February 19 in Los Vegas, ahead of the Nevada caucuses on February 22.