Donovan Slack

USA TODAY

Massachusetts Sen. Elizabeth Warren unleashed a tweetstorm against Donald Trump on Monday, knocking everything from his failed business dealings to his “insecurities” and “flagrant narcissism.”

The move ratchets up the back and forth between Trump and Warren, a Democrat whose populist rants against big banks have made her a darling of progressives. Warren posted (somewhat tamer) criticism of the New York republican last week on her Facebook page. That drew backlash from Trump, who told the New York Times that Warren is a "fraud."

Trump was asked at a press conference Monday afternoon about Warren's Twitter attacks. He at first called her an "Indian" — a reference to her controversial claims that she is part native American — and then called for unity.

"Who's that, the Indian? You mean the Indian?" Trump said.

"The problem with the country right now (is) it's so divided, and people like Elizabeth Warren really have to get their act together, because it's going to stay divided," he said. "And that includes Hillary and probably includes me, it includes everybody. This country has to get together, because we're in serious trouble."