Former Housing and Urban Development Secretary Julián Castro moved closer to a 2020 presidential run on Wednesday, announcing that he had set up an exploratory committee to test the waters for a potential bid.

"Americans are ready to climb out of this darkness. We're ready to keep our promises, and we're not going to wait. We're going to work," Castro said in a video statement posted on a website for the committee.

"That's why I'm exploring a candidacy for president of the United States in 2020."

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Castro, 44, said he would spend "the next several weeks" traveling across the country as he feels out support for a potential White House bid. He said plans to make a decision on Jan. 12 in his home state of Texas.

The exploratory committee, Julián for the Future, is the clearest signal yet that he is likely to seek the Democratic presidential nomination in 2020.

Such committees allow prospective presidential contenders to begin raising money ahead of a formal declaration of candidacy.

The early formation of the exploratory committee could give Castro a crucial head start in a potentially crowded Democratic primary field that could include political heavyweights like former Vice President Joe Biden Joe BidenBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Democratic groups using Bloomberg money to launch M in Spanish language ads in Florida Harris faces pivotal moment with Supreme Court battle MORE.

So far, the only Democrat who has declared a 2020 White House run is Rep. John Delaney John DelaneyCoronavirus Report: The Hill's Steve Clemons interviews Rep. Rodney Davis Eurasia Group founder Ian Bremmer says Trump right on China but wrong on WHO; CDC issues new guidance for large gatherings The Hill's Coronavirus Report: Kansas City Mayor Quinton Lucas says country needs to rethink what 'policing' means; US cases surpass 2 million with no end to pandemic in sight MORE (D-Md.), who has been campaigning for nearly a year and a half.

A handful of other would-be Democratic candidates have generated immense buzz, including another Texan: Rep. Beto O'Rourke Beto O'RourkeJimmy Carter says his son smoked pot with Willie Nelson on White House roof O'Rourke endorses Kennedy for Senate: 'A champion for the values we're most proud of' 2020 Democrats do convention Zoom call MORE (D).

O'Rourke emerged as a rising star in Democratic politics this year with his high-profile, though ultimately unsuccessful, Senate bid to unseat Sen. Ted Cruz Rafael (Ted) Edward CruzCruz blocks amended resolution honoring Ginsburg over language about her dying wish Trump argues full Supreme Court needed to settle potential election disputes Press: Notorious RBG vs Notorious GOP MORE (R-Texas). But that campaign helped him build an extensive network of donors and volunteers that would come in handy should he decide to mount a run for the White House.

Other possible contenders include Sens. Bernie Sanders Bernie SandersOutrage erupts over Breonna Taylor grand jury ruling Dimon: Wealth tax 'almost impossible to do' Grand jury charges no officers in Breonna Taylor death MORE (I-Vt.), Elizabeth Warren Elizabeth WarrenDimon: Wealth tax 'almost impossible to do' CNN's Don Lemon: 'Blow up the entire system' remark taken out of context Democrats shoot down talk of expanding Supreme Court MORE (D-Mass.), Kamala Harris Kamala HarrisHarris faces pivotal moment with Supreme Court battle Nearly 40 Democratic senators call for climate change questions in debates Joe Biden has long forgotten North Carolina: Today's visit is too late MORE (D-Calif.) and Cory Booker Cory Anthony BookerBipartisan praise pours in after Ginsburg's death DHS opens probe into allegations at Georgia ICE facility Democratic lawmakers call for an investigation into allegations of medical neglect at Georgia ICE facility MORE (D-N.J.).

Castro, who at one point was considered a possible running mate for 2016 Democratic nominee Hillary Clinton Hillary Diane Rodham ClintonDemocratic groups using Bloomberg money to launch M in Spanish language ads in Florida The Hill's Campaign Report: Presidential polls tighten weeks out from Election Day More than 50 Latino faith leaders endorse Biden MORE, has said for months that he is considering a run for president, but he hasn't garnered the same national attention as the likes of O'Rourke and some other Democrats.

In an interview with The Associated Press published Wednesday, the former San Antonio mayor suggested that he is likely to launch a campaign for the White House, saying that he knows "where I'm leaning, for sure."

He also said he's not worried about the buzz other potential Democratic contenders are generating, noting that it's still too early to determine which would-be candidates will emerge as the front-runner.

"It doesn't bother me that in December of 2018 I'm not right up at the top of the list," he told the AP. "If I decide to run, it would be because I believe I have a compelling message and I'm going to work hard and get to the voters and I believe I can be successful."

Castro’s announcement drew a sharp response from the Republican National Committee, which panned the former HUD secretary as an unqualified presidential contender.

“There’s arguably no bigger lightweight in the 2020 field than Julian Castro,” said RNC spokesman Michael Ahrens. His mayoral job was largely ceremonial, he was in totally over his head at HUD, and no, he doesn’t even know Spanish.”

Castro has said he understands Spanish, but does not speak the language fluently.

Castro will appear on “The Late Show with Stephen Colbert” alongside his brother, Rep. Joaquin Castro Joaquin CastroFlorida Democrat asks FBI to investigate anti-Semitic, racist disinformation Hispanic Caucus members embark on 'virtual bus tour' with Biden campaign Hispanic caucus report takes stock of accomplishments with eye toward 2021 MORE (D-Texas), to discuss his possible presidential plans on Thursday.

-- Updated 12:00 p.m.