President Donald Trump mocked Sen. Elizabeth Warren (D-Mass.) during a speech Thursday in Montana, and she took to Twitter soon after to respond.

Here's what the president said

"Should I lose or if I don't run," Trump told the Great Falls audience, "they're out of business! Who are they gonna cover? They're gonna cover Bernie? Hey. They're gonna cover like sleepy Joe Biden? They're gonna cover Pocahontas?"

"Think of it. Think of it," he repeated. "She of the great tribal heritage. What tribe is it? Uh let me think about that one."

"Meantime she's based her life on being a minority," he added. "Pocahontas, they always want me to apologize for saying it. And I hereby, and I want to apologize, Pocahontas I apologize to you, to you I apologize. To the fake Pocahontas I won't apologize."

"No it's causing her problems, you know that name, because now even the liberals are saying take a test. Take a test! You know I tell ya I shouldn't tell you because I like not to give away secrets, but," he continued.

"Let's say I'm debating Pocahontas, right?" he said. "I promise you I'll do this, you know those little kits they sell on television for $2. Learn your heritage!"

"Guys says I was born in Scotland, turns out he was born in Puerto Rico and that's OK, that's good," the president continued. "Guy says I was born in Germany, well he wasn't born in Germany, he was born some place else."

'Do it gently because we're in the 'me too' generation'

"I'm gonna get one of those kits and in the middle of the debate when she proclaims that she's of Indian heritage because her mother says she has high cheekbones, that's her only evidence that her mother said she has high cheekbones," he added.

"We will take that little kit, and say, but we have to do it gently because we're in the 'me too' generation so we have to do it very gently," Trump explained. "And we will very gently take that kit and we will slowly toss it hoping it doesn't hit her and injure her arm, even though it probably only weighs two ounces."

"And we will say I will give you a million dollars to your favorite charity, paid for by Trump, if you take the test and it shows you're an Indian, you know," he said to a loud applause from the audience. "And let's see what she does, right?"

Here's the video of Trump's attack on Liz Warren:

"I have a feeling she will say no," he concluded. "But we'll hold that for the debates, do me a favor, keep it within this room, cuz I don't want to give away any secrets."

'Focus on fixing the lives you’re destroying'

Warren angrily responded on her social media account and referenced the recent change in family separation policy at the border.

"Hey [President Donald Trump,]" she tweeted. "While you obsess over my genes, your Admin is conducting DNA tests on little kids because you ripped them from their mamas & you are too incompetent to reunite them in time to meet a court order."

"Maybe you should focus on fixing the lives you're destroying," she concluded.

Warren, one of the president's favorite punching bags and possibly a presidential candidate in 2020, was referring to news that the administration was using DNA tests to reunite children with their parents after being separated by the Immigration and Customs Enforcement agency at the border.