Presumptive GOP nominee Donald Trump again continued his attacks against Sen. Elizabeth Warren (D-MA), questioning her Native American heritage and saying that she was a woman who was ineffective and “only has a big mouth.”

“I think she is as Native American as I am. OK? That I will tell you. But she’s a woman that’s been very ineffective other than she’s got a big mouth,” Trump said at a press conference in North Dakota.

Trump referred to Warren as “Pocahontas” at least twice in the news conference. Someone in the crowd seemed to take issue with his name-calling which made him repeat the nickname.

“Is it offensive? You tell me. Oh, I’m sorry about that,” Trump said to someone in the crowd as a reporter asked a question about Warren. “Pocahontas is that what you said?”

He went on to say that Warren only got into schools because she applied as a Native American. Trump and Warren have had significant back and forth on Twitter. Trump has tended to attack her heritage and Warren has criticized his rhetoric toward females.