Presumptive Republican nominee Donald Trump is firing back after a recent attack by Democrat Sen. Elizabeth Warren on Twitter, shrugging off her criticism by saying, “Pocahontas is at it again!”

Pocahontas is at it again! Goofy Elizabeth Warren, one of the least productive U.S. Senators, has a nasty mouth. Hope she is V.P. choice. — Donald J. Trump (@realDonaldTrump) June 10, 2016

Trump’s tweet is in response to a speech Warren gave on Thursday, endorsing Hillary Clinton and attacking Trump for his rhetoric against Judge Gonzalo Curiel, who is overseeing a fraud cast against Trump University.

“If you break the law, you can be held accountable,” Warren stated.

The nickname “Pocahontas” is a reference to the controversy over whether or not Warren is actually Native American.