Bernie SandersBernard (Bernie) SandersAnti-abortion Dem wins primary fight Lipinski holds slim lead in tough Illinois primary fight Overnight Defense: Senate sides with Trump on military role in Yemen | Dem vets push for new war authorization on Iraq anniversary | General says time isn't 'right' for space corps MORE Sunday called on Democratic National Committee (DNC) Chairwoman Debbie Wasserman Schultz to resign following email leaks from within the party that showed officials tried to undermine his presidential campaign. 

She "should not be chair of the DNC, and I think these emails reiterate that reason why she should not be chair," the Vermont senator said on ABC's "This Week." 

"I think she should resign, period, and I think we need a new chair that's going to lead us in a new direction." 

Emails leaked by WikiLeaks Friday showed DNC officials privately planned how to undermine Sanders's presidential campaign. 

In one May 21 email, DNC press secretary Mark Paustenbach wrote to communications director Luis Miranda about planting a narrative to the media that Sanders’s “campaign was a mess.”

Sanders said Sunday the emails prove what he's been saying all along: The party favored presumptive presidential nominee Hillary ClintonHillary Diane Rodham ClintonKoch-backed group launches six-figure ad buy against Heitkamp Trump keeps up 'low IQ' attack on Maxine Waters GOP leaders to Trump: Leave Mueller alone MORE from the start. 

"Well, I think I told you a long time ago that the DNC was not running a fair operation — that they were supporting Secretary Clinton. So what I suggested to be true six months ago turns out, in fact, to be true," Sanders said.

"I'm not shocked by it, but I'm disappointed."