Clinton's Attacks on Sanders Draw Fire From Some Progressive Groups

— -- Hillary Clinton's attacks on Bernie Sanders' proposal for universal healthcare drew swift rebuke from Sanders campaign and some progressive groups.

In response to attack lines from both Clinton and her daughter Chelsea, the Sanders campaign pointed to a video of Clinton campaigning in 2008, where she took on then-Senator Barack Obama for criticizing her universal health care plan.

“Clinton’s attacks on a Democratic Party rival over universal health care marks a very public flip flop by her and her campaign," Sanders' team said. "She is now using the same Karl Rove tactics she once decried in this video.”

The Clinton campaign said that "Sanders hasn't explained how he would achieve" universal healthcare. "And that's because he doesn't want to admit he would rely on a broad tax increase on the middle class to pay for it," they added.

In recent days, Clinton and her campaign has increased the tempo of their attacks against the Vermont Senator, drawing criticism from progressives.

Charles Chamberlain, Executive Director of Democracy for America, which endorsed Sanders, called Clinton’s attack “bald faced lies” that have “no place in a Democratic primary.”

“The goal of Democrats holding on to the White House in 2016 is being made more difficult every second the Clinton campaign continues to distort the facts on Bernie Sanders's strong record against gun violence and attack a core progressive idea like universal healthcare,” Chamberlain wrote in a statement.

Similarly, National Nurses United, which has also endorsed Sanders, said the Clinton campaign was purposely misconstruing Sanders’ health care plan by claiming it would give autonomy to state governors.

“To claim that expanding Medicare to all would hand it over to state governors is a crude, inflammatory distortion, and shows an indifference to all those people who continue to be harmed by a broken system,” NNU co-President Jean Ross said.

ABC News' Liz Kreutz contributed reporting.