"We're nearly a year into the Democratic primary and no other candidate has put out anything close to my sweeping plan to root out Washington corruption. Now, some candidates have at least put forward campaign finance reform plans, but if you want to know about a candidate's commitment to reform, don't just look at what they say they will do -- look at what they're doing right now," Warren said.
"Most candidates haven't disclosed the names of their bundlers or finance committees. They are spending time in fundraisers with high-dollar donors, selling access to their time for money. Some of them have spent months blocking reporters from entering those fancy, closed-door affairs. We know that one Democratic candidate walked into a room of wealthy donors this year to promise that 'nothing would fundamentally change' if he's elected president," Warren added, referring to both Buttigieg and Biden, respectively.
Warren's criticism comes on the heels of a weeks-long feud over transparency with Buttigieg, which led both candidates to release more information about their time working for big companies: Buttigieg for McKinsey and Co. and Warren as a bankruptcy lawyer for companies like Dow Chemical and Travelers Insurance.
Buttigieg has also recently decided to open his fundraisers to the press and pledged to release the names of his bundlers -- a political term for people who pull together fundraising money from different donors for the campaigns -- as well as who serves on his financial committee, all after calls last week from Warren to show "what promises he's making to rich folks and what he's saying that's different from what he says when he's out on the trail."
Buttigieg hasn't released a list of bundlers since April.
As for Biden, Warren's criticism referred to comments the front-runner made earlier this year to donors, expressing that he didn't think wealthy people should be demonized and assuring the room that "nothing would fundamentally change" if he was elected.
In her speech, Warren contrasted Biden and Buttigieg's high-dollar fundraisers with her own campaign, which she has pledged to run without doing any closed-door fundraisers.
"Look, I don't ask for a thousand dollar contribution in exchange for a picture. I'm closing in on 100,000 selfies for a grand total of zero dollars," Warren said. Warren, who promises voters at most town halls that she'll stay to take photos with whoever wants one, took her 90,000th photo at a rally in Chicago after Thanksgiving.
Though the Thursday speech was chock-full of wealth disparity statistics and the dozens of plans Warren has proposed to address economic issues facing families, most notable were the dozens of critiques she launched at her fellow Democratic candidates -- part of a growing trend for Warren, who largely refused to "bash" other Democrats in earlier stages of the primary.
Asked if the intent of her speech was to argue that she was the only Democrat in the race who could fix the problems facing America, Warren said, "pretty much."
"I mean, look we know how bad the problems are right now, no one is proposing the kinds of solutions that address those problems. We have a serious problem in America with corruption, with a Washington that keeps working better and better and better for those at the top and not much for anyone else," she told reporters after the speech. "But Americans know this all across the country and it means in a Democratic primary, that's a problem we should be wrestling with, it's one we should be attacking head on -- and it's just not happening."
While Warren never mentioned Biden or Buttigieg by name, she was clear in her words on Thursday, quoting Biden and listing specific examples from Buttigieg's campaign more than once.
"Now, unlike some candidates for the Democratic nomination, I am not counting on Republican politicians having an epiphany and suddenly supporting the kinds of tax increases on the rich or big business accountability that they've opposed under Democratic presidents for a generation," Warren said in the speech, drawing on comments Biden made in May about working across the aisle with Republicans.
"The thing that will fundamentally change things is with Donald Trump out of the White House. Not a joke," Biden told reporters at the time. "You will see an epiphany occur among many of my Republican friends."
Warren, on the other hand, has argued that Democrats will not win by campaigning on a return to the era before Trump, but rather that they should fight for "big, structural change."
"Unlike some candidates for the Democratic nomination, I'm not betting my agenda on the naive hope that if Democrats adopt Republican critiques of progressive policies or make vague calls for unity that somehow the wealthy and well-connected will stand down," Warren said in her speech Thursday.
Her comments about "progressive policies" and "Republican critiques" referred to criticism from both Biden and Buttigieg after she released details on her vision of Medicare for All plan back in November.
While Biden and Buttigieg, who support a public option for health care but do not support getting rid of private insurance companies, argued that the math behind her plan didn't add up and that Medicare for All would be too disruptive, Warren said their arguments against her plan were recycled talking points often heard on the Republican side.
In response to Warren's speech on Thursday, senior communications adviser for Buttigieg, Lis Smith, said Warren's "idea of how to defeat Donald Trump is to tell people who don't support her that they are unwelcome in the fight and that those who disagree with her belong in the other party."
"We need to move beyond the politics and divisiveness that is tearing this country apart and holding us back. Pete will be a President who will heal our divides and rally Americans around big ideas to solve the problems that have festered in Washington for too long," Smith said in a statement.
The Biden campaign declined to comment to ABC News, though the candidate did make an apparent reference to the Warren speech at a fundraiser late Thursday.
"I read a speech by one of my -- good person -- one of my opponents, saying that, 'You know, Biden says we’re going to have to work with Republicans to get stuff passed,’” Biden said to chuckles from the audience in Palo Alto, California. “I thought, ‘Well, OK -- how are you going to do it, by executive order?’”
The three Democrats will meet face-to-face on the debate stage next Thursday in Los Angeles for the sixth Democratic debate.
ABC News' Justin Gomez and Molly Nagle contributed to this report.