Story highlights Sanders called Clinton part of "establishment politics and establishment economics" in an interview with CNN's Wolf Blitzer

Sanders also questioned Clinton's assertion that she is progressive

(CNN) Bernie Sanders on Wednesday hammered Hillary Clinton's super PAC's fundraising haul, playing up his $3.5 million in individual contributions following the Iowa caucuses.

The Vermont senator called Clinton part of "establishment politics and establishment economics" in an interview with CNN's Wolf Blitzer.

He pointed to Clinton's Priorities USA Action, which reported raising $25.3 million in the second half of 2015 -- including, Sanders said, $15 million attached to Wall Street interests.

"That is a very significant difference," he said. "Our campaign is funded by the people. To a significant degree, her campaign is funded by Wall Street and big money interests."

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Sanders also questioned Clinton's assertion that she is progressive, pointing to the months she waited before announcing her opposition to the Trans-Pacific Partnership trade deal and the Keystone XL pipeline

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