Sen. Elizabeth Warren, who has faced repeated ridicule from President Donald Trump for claiming that she is of Native American descent, released a DNA test on Monday that says there is "strong evidence" to back up her claim.

The release of the test highlights how prepared Warren is to take on Trump — who has referred to her as "Pocahontas" — over the insults and suggests the Massachusetts Democrat is working to shore up potential political weaknesses before a possible 2020 presidential run by addressing charges that she misrepresented her family background to gain unfair advantage in her career.

Warren's DNA test was first reported by The Boston Globe, which obtained news of the results before they were released by the senator.

The test, conducted by Stanford University professor Carlos Bustamante, a genetics and genomics expert, concludes that there is "strong evidence" that Warren's "DNA sample of primarily European descent also contains Native American ancestry from an ancestor in the sample's pedigree 6-10 generations ago," according to the test's executive summary.

According to the summary, Bustamante concludes with 99 percent confidence that Warren's DNA sample contains five genetic segments, spanning 12.3 million DNA bases, which are "Native American in origin." The report also details the results of "several additional analyses to confirm the presence of Native American ancestry and to estimate the position" of an "unadmixed Native American Ancestor" — meaning an ancestor with "100 percent ancestry assigned to a single population" — in Warren's family tree.

Warren also released a video along with the results that not only seeks to address head-on the single biggest attack leveled against her by Republican critics, but offers the intensely personal Warren a platform to introduce herself to a larger audience.

She retraces her roots in Norman, Oklahoma, "on the ragged edge of the middle class," and the "twists and turns" that followed in her personal and professional life.

The video includes testimony from three of her brothers, a nephew, and a cousin who is a Cherokee Nation citizen. They note that her father's family was bitterly opposed to her parents' marriage because of her mother's claims of Native American heritage.

It also features faculty members from various colleges and universities where Warren taught, backing up Warren's assertion that her background "played no role in my hiring."

The video also shows Warren receiving the test results from Bustamante in a phone call.

"The president likes to call my mom a liar. What do the facts say?" Warren tells Bustamante on the phone in the video.

"The facts suggest that you absolutely have Native American ancestry in your pedigree," Bustamante responds.

Trump quickly dismissed Warren's latest move.

"Who cares?" the president told reporters Monday when told about the test. "I hope she's running for president because she’s easy, she wants to make the U.S. Venezuela."

Later, when asked if he owes Warren an apology: "She owes the country an apology. What is the percentage (Native American)? 1/1000th?"

Warren has sought to address the controversy before in a more muted way. In February, she addressed the National Congress of American Indians, where she reiterated that her claims of ancestry were based on the story passed down through her family, but acknowledged that only Native American tribes truly determine citizenship.

In that speech, she explained that her mother's family was "part-Native American" and that her parents eloped in 1932 because her father's family opposed the relationship.

Warren also said that she "never used my family tree to get a break or get ahead" and "never used it to advance my career."

Warren has faced repeated attacks from Trump over her claims that she is of Native American descent. He began using the "Pocahontas" slur to attack Warren during the 2016 campaign, and has said that Warren had "made up her heritage, which I think is racist."

In July, at a rally in Montana, he challenged Warren to take a DNA test and said he would pay $1 million to her "favorite charity if you take the test and it shows you're an Indian."

"You know those little [DNA] kits they sell on television for $2?" he said then. "I’m going to get one of those little kits and in the middle of the debate, when she proclaims she’s of Indian heritage because her mother said she has high cheekbones."

"We will take that little kit and say, but we have to do it very gently because we’re in the ‘MeToo’ generation … and we will very gently take that kit and we will slowly toss it, hoping it doesn’t hit her and injure her arm ... and we will say I will give you $1 million to your favorite charity, paid for by Trump, if you take the test and it shows you’re an Indian," Trump added. "I have a feeling she will say no."

Trump said later Monday he would only pay the $1 million "if I can test her personally. That will not be something I would enjoy doing, either."

Warren reminded Trump of his promise, urging him to donate the sum to the National Indigenous Women's Resource Center. She also called on Trump to release his tax returns.

NIWRC is a nonprofit working to protect Native women from violence. More than half of all Native women have experienced sexual violence, and the majority of violent crimes against Native Americans are perpetrated by non-Natives.



Send them your $1M check, @realDonaldTrump. — Elizabeth Warren (@elizabethforma) October 15, 2018

I took this test and released the results for anyone who cares to see because I’ve got nothing to hide. What are YOU hiding, @realDonaldTrump? Release your tax returns – or the Democratic-led House will do it for you soon enough. Tick-tock, Mr President. — Elizabeth Warren (@elizabethforma) October 15, 2018

In his comments to reporters earlier Monday, Trump said he never made such a promise. "I didn't say that. You better read it again," he said.

Later, after Trump's comments, Warren tweeted again, responding to the president's denial by saying, "Having some memory problems, @realDonaldTrump? Should we call for a doctor?"

Having some memory problems, @realDonaldTrump? Should we call for a doctor?



Here’s something you won’t “forget,” Mr. President: You’re the least popular president in modern history & your allies will go down hard in the midterm elections. 22 days. Tick-tock, tick-tock. pic.twitter.com/53FV0HXGXX — Elizabeth Warren (@elizabethforma) October 15, 2018

As recently as last week, Trump lobbed the attack line at Warren, saying at a rally in Kansas that “I’ve got more Indian blood in me than Pocahontas, and I have none."

Warren faced similar attacks about her heritage during her 2012 Senate race against Republican Scott Brown, who claimed she had dishonestly listed herself as Native American while working as a faculty member at the University of Pennsylvania and Harvard to help her career.

Warren denied the charges. And in a precursor to Monday’s announcement, Warren’s campaign in September produced personnel files and other documents related to her academic career at six universities. A Boston Globe analysis of the documents and interviews with officials involved in her hiring "found clear evidence … that her claim to Native American ethnicity was never considered” in her hiring.