After months of an above-the-fray strategy, Sen. Elizabeth Warren is harshly criticizing 2020 Democratic rivals Joe Biden and Pete Buttigieg, calling them Republicans-lite and afraid to defend Democratic values.

In a New Hampshire speech Thursday, the Massachusetts senator unleashed some of her most scathing invective against the top-tier pair of opponents.

“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,” she said. “Unlike some candidates for the Democratic nomination, I'm not counting on Republican politicians having an epiphany and suddenly supporting the kinds of tax increases on the rich or big business accountability they have opposed under Democratic presidents for a generation."

Those lines were implicit critiques of campaign pitches by Biden, the former vice president and Delaware senator, 77, and Buttigieg, the 37-year-old South Bend, Indiana, mayor. Both have told Democratic voters that they believe they can help the country recover from what they call President Trump's divisive tenure and find common ground with congressional Republicans.

Last week, Biden told voters at a town hall that he plans to "unite the country." He has often told Democrats that having an opposition party is necessary to maintain a stable country.

[ Related: Healer-in-chief? Joe Biden stakes candidacy on promise to bring Americans together in post-Trump era]

Buttigieg's campaign responded to Warren's jabs preemptively, having seen text of her upcoming speech.

“Sen. 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," wrote Buttigieg spokeswoman and strategist Lis Smith in a statement. "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.”

The back-and-forth between the campaigns comes after Warren and Buttigieg engaged in a feud over making public details about their past corporate work. Warren repeatedly demanded Buttigieg release details of his clients at management consulting firm McKinsey & Co. Buttigieg, in turn, insisted she be more transparent about her legal work, outside of her law school professor jobs, which netted her nearly $2 million over three decades.

Recent polling has shown Warren losing ground to Buttigieg, Biden, and Sen. Bernie Sanders. A Monmouth University survey released Tuesday found her support at 17%, compared to Sanders's 21%, and Biden's 26%.

In the early primary states of Iowa and New Hampshire, Warren has been relegated to third and fourth place, respectively. A RealClearPolitics average has Warren's support at 16.3% in Iowa and 13.3% in New Hampshire.