Bernie Sanders said Wednesday that Hillary Clinton was not "qualified" to be president, citing the fact that a super PAC supporting her campaign takes "tens of millions of dollars in special interest funds."
"She has been saying lately that I am 'not qualified' to be president. Well let me just say in response to Secretary Clinton: I don't believe that she is qualified if she is through her super PAC taking tens of millions of dollars in special interest funds," Sanders told supporters in Philadelphia.
PHOTOS: Bernie Sanders on the campaign trail
Bernie Sanders on the campaign trail
Bernie Sanders: Hillary Clinton not 'qualified' to be president
PHOENIX, AZ - MARCH 15: Democratic presidential candidate Sen. Bernie Sanders (D-VT) speaks to a crowd gathered at the Phoenix Convention Center during a campaign rally on March 15, 2016 in Phoenix, Arizona. Hillary Clinton won the Democratic primary elections in Florida, North Carolina and Ohio, while Missouri and Illinois remain tight races. (Photo by Ralph Freso/Getty Images)
DES MOINES, IA - JANUARY 26: Democratic presidential candidate Sen. Bernie Sanders (I-VT) speaks to the media after holding a campaign event with United Steelworkers Local 310L, on January 26, 2016 in Des Moines, Iowa. Sanders continues his quest to become the Democratic presidential nominee.. (Photo by Joe Raedle/Getty Images)
TOPSHOT - US Senator and Democratic Presidential Candidate Bernie Sanders speaks during a campaign event at the University of Northern Iowa in Cedar Falls, Iowa, January 24, 2016, ahead of the Iowa Caucus. / AFP / JIM WATSON (Photo credit should read JIM WATSON/AFP/Getty Images)
Senator Bernie Sanders, an independent from Vermont and 2016 Democratic presidential candidate, participates in the Democratic presidential candidate debate in Charleston, South Carolina, U.S., on Sunday, Jan. 17, 2016. Hours before Sunday's Democratic debate, the two top Democratic contenders held a warm-up bout of sorts in multiple separate appearances on political talk shows, at a time when the polling gap between the pair has narrowed in early-voting states. Photographer: Patrick T. Fallon/Bloomberg via Getty Images
NEW YORK, NY - JANUARY 05: Democratic presidential candidate Sen. Bernie Sanders (I-VT) shakes hands with supporters after outlining his plan to reform the U.S. financial sector on January 5, 2016 in New York City. Sanders is demanding greater financial oversight and greater government action for banks and individuals that break financial laws. (Photo by Andrew Burton/Getty Images)
LEBANON, NH - NOVEMBER 11: Presidential candidate Bernie Sanders (I-VT) marches in the Veterans Day Parade November 11, 2015 in Lebanon, New Hampshire. Sanders goes into the Democrats second debate this weekend still running strong in the polls.(Photo by Darren McCollester/Getty Images)
Senator Bernie Sanders, an independent from Vermont and 2016 Democratic presidential candidate, speaks at the Congressional Hispanic Caucus Institute conference in Washington, D.C., U.S., on Wednesday, Oct. 7, 2015. While next Tuesday's first Democratic presidential debate will probably lack the name-calling and sharp jabs of the Republican face-offs, there's still potential for strong disagreements between the party's leading contenders. Photographer: Andrew Harrer/Bloomberg via Getty Images
Democratic Presidential candidate Senator Bernie Sanders speaks about the Workplace Democracy Act on Capitol Hill in Washington, DC on October 6, 2015. AFP PHOTO/JIM WATSON (Photo credit should read JIM WATSON/AFP/Getty Images)
US Senator from Vermont and Democratic presidential candidate Bernie Sanders addresses striking low-wage contract workers from the US Capitol and religious leaders at the Lutheran Church of the Reformation in Washington, DC, on September 22, 2015 for an interfaith service ahead of the arrival of Pope Francis for a six-day visit to the US. AFP PHOTO/NICHOLAS KAMM (Photo credit should read NICHOLAS KAMM/AFP/Getty Images)
MANCHESTER, NH - SEPTEMBER 19: Democratic Presidential candidate Senator Bernie Sanders (I-VT) talks on stage during the New Hampshire Democratic Party State Convention on September 19, 2015 in Manchester, New Hampshire. Five Democratic presidential candidates are all expected to address the crowd inside the Verizon Wireless Arena. (Photo by Scott Eisen/Getty Images)
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He also cited Wall Street donations Clinton's super PAC has received and her vote in support of the Iraq War as well as her position on trade.
The new, sharply aggressive tone in the race comes one day after Sanders picked up a win in Wisconsin, his sixth victory in the past seven contests. Both campaigns are gearing up for a brutal race in New York, the state Clinton represented as senator and where Sanders was born and raised before moving to Vermont. Even after her loss in Wisconsin, Clinton leads Sanders comfortably in the delegate race. Still, a loss in New York would raise questions about her campaign and why Sanders continues to trounce her in some states.
A Clinton spokesman on Twitter described Sanders' comments as a "new low" in the race.
In an interview earlier Wednesday, Clinton similarly questioned whether Sanders was qualified to serve as president.
"I think he hadn't done his homework and he'd been talking for more than a year about doing things that he obviously hadn't really studied or understood," Clinton told MSNBC's "Morning Joe," saying "that does raise a lot of questions."
"Really, what that goes to is for voters to ask themselves: 'Can he deliver what he's talking about,'" Clinton said.
Clinton's comments came after a New York Daily News interview in which Sanders' responses were widely criticized, particularly his inability to explain a key platform of his campaign: how he would break up the biggest banks.
Clinton and Sanders are set to face off in an April 14 debate, days before New York's voters head to the polls.
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