Image copyright Reuters Image caption President Donald Trump and Republicans have taunted the Democrat over her reported Native American heritage

US Senator Elizabeth Warren has revealed that a DNA test shows "strong evidence" that she has distant Native American ancestry.

She took the test after President Donald Trump taunted her in speeches, calling her a "fake Pocahontas" and challenging her to take the test.

The DNA test suggests Ms Warren has a Native American ancestor dating back six to 10 generations.

Many believe the Democrat is preparing for a presidential bid in 2020.

What exactly was revealed?

Ms Warren, who is up for re-election in Massachusetts, shared the report along with a video of family and colleagues discussing her heritage on Monday.

The DNA report was conducted by geneticist Carlos Bustamante of Stanford.

"The vast majority" of Ms Warren's ancestry is European, it concludes, but "the results strongly support" a Native American ancestor.

This puts Ms Warren as between 1/64 and 1/1,024 Native-American, according to the Boston Globe.

Ms Warren herself is not a part of any native tribe. While the results of the test do confirm there is native heritage in Ms Warren's family tree, critics could still point out how imprecise these DNA tests can be.

Cherokee Nation Secretary of State Chuck Hoskin Jr said in a statement on Monday that "a DNA test is useless to determine tribal citizenship", adding that sovereign tribal nations have their own legal requirements.

"Using a DNA test to lay claim to any connection to the Cherokee Nation or any tribal nation, even vaguely, is inappropriate and wrong," Mr Hoskin said.

"It makes a mockery out of DNA tests and its legitimate uses while also dishonouring legitimate tribal governments and their citizens, whose ancestors are well documented and whose heritage is proven."

The senator's accompanying video begins with a clip of the president mocking her at a rally, saying: "She said she's Native-American and I said, Pocahontas!"

Content is not available

Pocahontas was the daughter of a 17th-Century indigenous chief.

The video shows Ms Warren's family - including brothers who say they are Republicans - criticising the president's taunts.

A cousin who is identified as being a member of the Cherokee Nation adds: "It's offensive to me, not just as Betsy's cousin, but as a Native-American."

Analysis: A clear move

By Anthony Zurcher, North America correspondent

Elizabeth Warren has been a star of the progressive left for years. Now - even before November mid-terms in which she's running for re-election to the Senate - she's making the clearest moves toward a bid for the Democratic presidential nomination in 2020.

Part of that preparatory process is fortifying her defence against Donald Trump's repeated questions about her claims of Native American heritage, including his derisive references to her as "Pocahontas". With positive DNA test results in hand, she's pushing back - and reiterating that she did not use her ancestry to advance her academic career.

That probably won't stop Mr Trump's attacks, but it will allow her to deflect the barbs and move on to what could be the top issues of an increasingly less hypothetical run - income inequality and government ethics reform.

It's unusual to see a presidential primary field begin to take shape more than two years before election day. With so many potential candidates eyeing the race, however, there's an advantage to moving quickly. Ms Warren could face a fierce fight for the progressive vote against an electoral powerhouse such as Bernie Sanders.

If she's going to prevail, every moment counts.

How has Warren been taunted?

Ms Warren has denied benefiting from her background since 2012, when it emerged that she was listed as a minority in a Harvard Law School directory.

She has frequently faced attacks from the White House and Republicans over whether she used claims of native ancestry to advance her career.

At a rally in July, the president said he would give $1m (£761,000) to charity if Ms Warren would prove her claims of Native-American heritage.

In 2012, two Republican aides were recorded making offensive gestures linked to Native Americans while poking fun at then-candidate Ms Warren.

Asked about the DNA test, Kellyanne Conway, White House counsellor, told reporters: "Everybody likes to pick their junk science and sound science depending on the conclusion."

Media playback is unsupported on your device Media caption President Trump goads Senator Elizabeth Warren with #MeToo jibe

One clip in the new video shows White House Press Secretary Sarah Sanders saying: "What most people find offensive is Senator Warren lying about her heritage to advance her career."

In response, the video has a number of Ms Warren's colleagues and employers affirm that her background paid no role in her hiring.

Her campaign has also shared a number of documents and testimonials stating Ms Warren's ancestry did not impact upon her career.

In the video, Ms Warren says her critics attack her as an insult or "to distract from the kinds of changes I'm fighting for".

"Trump can say whatever he wants about me, but mocking Native Americans or any group in order to get at me?" she asks. "That's not what America stands for."

How does this echo Trump attacks on Obama?

The hubbub around Ms Warren's ancestry recalls the attacks President Barack Obama faced over his background.

Media playback is unsupported on your device Media caption What young people think of Democratic Party's future

During Mr Obama's campaign, Mr Trump called repeatedly for him to release his birth certificate to prove he was born in America.

The rumours that Mr Obama was a foreigner persisted throughout his presidency and, in 2011, the White House released his birth certificate to quash the controversy.