During a fundraiser for former Vice President Joe Biden in Chicago on Thursday, billionaire casino and real estate magnate Neil Bluhm said Sen. Bernie Sanders doesn't represent the Democratic Party Bluhm supports, drawing a quick retort from the Vermont presidential contender.

Sanders expressed agreement with Bluhm, whose casinos have a history of union-busting and other anti-worker abuses.

"Mr. Bluhm is right—the Democratic Party I represent is the party of the working class, not billionaires," said the Vermont senator. "That's why we're going to win."

In a statement to @CNN in response to this report @BernieSanders said: “Mr Bluhm is right -- the Democratic Party I represent is the party of the working class, not billionaires. That's why we're going to win.” https://t.co/Ti9gSCJCpi — Ryan Nobles (@ryanobles) September 19, 2019

Bluhm's attack on Sanders and Sen. Elizabeth Warren (D-Mass.)—Biden's closest rivals in the 2020 Democratic presidential race—came during one of three high-dollar fundraisers the former vice president attended in Chicago on Thursday.

Sanders, meanwhile, participated in MSNBC's climate forum Thursday before rallying at the University of North Carolina, Chapel Hill as part of his "college tour."

During the North Carolina event, Sanders contrasted his grassroots approach with Biden's reliance on big-money fundraisers. Emphasizing the point, Sanders highlighted news that his campaign reached the milestone of one million individual donors on Thursday.

"I would say to him, 'Joe, we are not going to make the changes we need in this country when you go to three fundraisers in Chicago sponsored by multi-millionaires,'" said Sanders.

"We are going to make the changes that we need in this country," added the senator, "when the working people of America stand up to the corporate elite, not take their money."

As Common Dreams reported Thursday, the Sanders campaign said teachers represented the most common profession among the senator's donors. The top employers of Sanders donors, according to the campaign, are Starbucks, Amazon, and Walmart.