Washington (CNN) Democratic front-runner Hillary Clinton says she's brushing off Republican front-runner Donald Trump's attacks on her -- especially since he used to sing her praises -- but his schtick "is no longer amusing."

Clinton said Trump's attacks on her are an example of Trump's "demagoguery," that he will say whatever he feels will advance his cause.

Speaking with MSNBC host Al Sharpton in an interview to air this weekend, Clinton was asked about Trump and how he has called her "shrill."

"He's called me a lot of things -- now that he's running against me," Clinton said in an excerpt of the interview aired on "Morning Joe" on MSNBC on Friday. "Before, he called me a great senator and a great secretary of state. That's what a demagogue does: They say whatever they need to say to try to stir up the passions of people."

Clinton also slammed Trump for his rhetoric on immigration.

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