Massachusetts Sen. Elizabeth Warren took a formal step toward a potential 2020 presidential campaign Monday morning, announcing in an email to supporters and video message on social media that she is forming an exploratory committee to test the viability of a bid for the White House.

The Federal Election Commission posted her statement of organization later in the day. The Massachusetts Democrat expanded on her plans later in the day. She plans to begin traveling to the early-voting primary and caucus states soon. The exploratory committee will enable her to raise money to pay for that travel and to hire staff for this effort.

"The problem we've got right now in Washington is that it works great for those who've got money to buy influence, and I'm fighting against that, and you bet it's going to make a lot of people unhappy," said Warren, who spoke in generalities when reporters asked about her reason for running Monday afternoon.

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In her letter to supporters Monday morning, Warren said that she "never in a zillion years" thought she would run for office. By afternoon, Warren claimed she had already received donations from all 50 states, Puerto Rico and Washington, D.C.

In a video released on social media, Warren said she's running in order to take a stand for middle-class Americans. She lays out the vision for her presidency in the video as one in which democracy and our economy "work for all of us."

"In our country if you work hard and play by the rules, you ought to be able to take care of yourself and the people you love. That's a fundamental promise of America," she said. Warren talked about her own family's struggles -- her father was a janitor and her mother worked at Sears -- and yet, Warren grew up to be be a teacher, a law professor and a senator. Now, she believes "working families today face a lot tougher path than my family did. And families of color face a path that is steeper and rockier. A path made even harder by the impact of generations of discrimination."

While Warren represents Massachusetts, she was born and raised in Oklahoma, attended college in New Jersey, and taught at law schools in Texas and Pennsylvania before her Harvard job. Former students include Rep. Joseph Kennedy, D-Mass., and incoming Rep. Katie Porter, D-Calif.

The Massachusetts senator, who just won re-election to her second Senate term and will be sworn in Thursday, said in September that she'd take a "hard look" at a bid for the White House after the midterms.

Avid 2020 watchers noted that a couple of days ago Warren changed her campaign Twitter account from @ElizabethForMA to a more general handle -- @EWarren -- according to a bot that tracks changes in congressional Twitter accounts.

Over the past month, Warren has been personally reaching out to key Democratic constituencies in early-voting states, according to media reports. The Des Moines Register reported that top Iowa Democrats are among those she's been talking to as she mulls the viability of a presidential campaign. "She's not calling me to ask about the weather or my Christmas plans," Tri-County Democrats Chairman Kurt Meyer told the Des Moines Register. Warren phoned him in early December.

In late November Warren delivered a speech staking out positions on foreign policy issues, like the president's new trade agreement with Mexico and Canada and American involvement in Afghanistan.

In the fall, the Massachusetts Democrat also released the results of a DNA test that she says shows she has some Native American heritage. She explained that she had done so to show "I won't sit quietly for @realDonaldTrump's racism."

President Trump has often taunted Warren, dubbing her "Pocahontas" to mock her claims of Native American heritage, and he had offered her $1 million to take a DNA test. However, once she took the test, he added the caveat that he would have to administer the test himself.

To announce the results of the DNA test, Warren used a campaign-style video that tried to directly address questions about her heritage. It's a controversy that has dogged Warren since she first ran for the Senate six years ago.

In an interview with Fox News on Monday, Mr. Trump again commented on Warren's heritage. "She did very badly in proving that she was of Indian heritage. That didn't work out too well," the president told "All-American New Year" co-host Pete Hegseth. "I think you have more than she does, and maybe I do too and I have nothing. So, we'll see how she does, I wish her well, I hope she does well, I'd love to run against her."

Ronna McDaniel, the Republican National Committee chairwoman, said that Warren's candidacy "couldn't be more out of touch."

"With her lack of support from voters – including in her home state – on top of her phony claim to minority status, now that she is formally running Americans will see her for what she is: another extreme far-left obstructionist and a total fraud," McDaniel said in a statement. "Voters know President Trump's agenda gets results and they will make their voices heard at the ballot box in 2020."

Warren is a staunch consumer advocate who played a key role in the establishment of the Consumer Financial Protection Bureau during the Obama administration. She's also a former Harvard professor known for her progressive politics and her populist views on the economy.

Jack Turman, Grace Segers and Alex Sundby contributed to this report.