Donald Trump referred to Sen. Elizabeth Warren (D-MA) as “the Indian” during a Monday press conference on the grounds of his new Washington, D.C. hotel.

Earlier Monday the Massachusetts senator had gone on a social media rant against the Republican frontrunner, calling him a “loser” who wants to “tear apart” the country. Asked to respond during a press conference at the Old Post Office Pavilion, Trump replied, “Who is that, the Indian? You mean the Indian?”

The reporter continued with her line of questioning, asking how Trump would handle sustained attacks from figures like Warren and Democratic presidential frontrunner Hillary Clinton.

“The problem with the country right now, it’s so divided and people like Elizabeth Warren really have to get their act together because its gonna stay divided,” Trump said. “And that includes Hillary and probably includes me. It includes everyone cause we’re in trouble.”

Warren’s unsubstantiated claims that she has Cherokee ancestry became a focus in the 2012 Massachusetts Senate race. Warren, who was raised in Oklahoma, said she learned of her Native American heritage through family lore.

“These are my family stories,” Warren said at the time. “This is what my brothers and I were told by my mom and my dad, my mammaw and my pappaw.”

Trump has previously mocked Warren’s claims.

“She’s caught a little wave. Perhaps it’s her Indian upbringing,” Trump told the New York Times’ Maureen Dowd in August. As Buzzfeed reported at the time, Trump has repeatedly falsely claimed that his family immigrated to the U.S. from Sweden.

Warren fired back on Twitter Monday afternoon, saying Trump was fine with being called “authoritarian.”