US Senator Elizabeth Warren, a liberal firebrand who has taken on Wall Street and traded barbs with Donald Trump, on Monday became the most prominent Democrat to announce a challenge to the Republican president in 2020. Warren said she had formed an exploratory committee, which will allow her to begin raising money to compete in what is expected to be a crowded Democratic primary field before the November 2020 presidential election.

She said on Twitter she would announce her decision on whether to run early in 2019. Warren, 69, a senator from Massachusetts since 2013, became one of Trump's fiercest critics during the 2016 presidential race and they have continued to exchange biting insults during his presidency. Trump mockingly refers to her as "Pocahontas" because of her claim to Native American ancestry.

Warren has denounced Trump as an "insecure money grubber" with a platform of "racism, sexism and xenophobia" while Trump has described the former Harvard Law School professor as "goofy" and a "lowlife" with "a nasty mouth."

Several hours after the announcement, Trump had not responded but Republican National Committee Chairwoman Ronna McDaniel said on Twitter that Warren was "another extreme far-left obstructionist and a total fraud."

On Monday, Warren released a video in which she outlines her vision of a path to opportunity for all Americans, not just the wealthy.

"America's middle class is under attack," she says on the video. "How did we get here? Billionaires and big corporations decided they wanted more of the pie and they enlisted politicians to cut them a fatter slice."

Copyright Reuters, 2019