Sen. Bernie Sanders (I., Vt.) said Sunday morning that leaked remarks from a Hillary Clinton fundraiser bothered him.

Sanders appeared on CNN’s State of the Union and was asked by host Jake Tapper about the audio, which was first reported last week by the Washington Free Beacon.

"She’s calling other ideas you pitch not the ones that you two are working on together, but she called other ones false promises and said what you were doing was indefensible," Tapper said. "That must bother you."

"Of course it does," Sanders responded.

Sanders also noted that he and Clinton still share differences over policy and ideology.

"If you go to some of the statements that I made about Hillary Clinton, you could see real differences," Sanders said.

In audio released from a fundraiser in February, Clinton can be heard expressing bewilderment at some of the policies supported by Sanders and his supporters.

They are children of the great recession and they are living in their parents’ basement. So if you’re feeling that you’re consigned to being a barista or, you know, some other job that doesn’t pay a lot and doesn’t have much of a ladder of opportunity attached to it. Then the idea that maybe, just maybe, you could be part of a political revolution is pretty appealing.

Sanders has started to appear more regularly with Clinton o the campaign trail as polls have shown her struggling with millennial voters. Clinton’s campaign has been unable to attract the younger voters that made up a big part of Sanders’ Democratic primary coalition.

Sanders will campaign for Clinton in Iowa and Minnesota on Monday and Tuesday.