Sen. Elizabeth Warren labeled Donald Trump a loser, a bully and a threat on Monday, continuing a fierce war of words between the liberal icon and the front-running Republican presidential candidate that has played out on social media and The New York Times.

WASHINGTON, DC - JULY 21: Sen. Elizabeth Warren (D-MA) delivers remarks during a news conference on the fifth anniversary of the Dodd-Frank Wall Street Reform and Consumer Protection Act at the U.S. Capitol Visitors Center July 21, 2015 in Washington, DC. Before being elected to the U.S. Senate, Warren helped craft the legislation that created the Consumer Financial Protection Bureau which has helped return $10 billion to 17 million consumers since it was created in 2011. (Photo by Chip Somodevilla/Getty Images)
Sen. Elizabeth Warren (D-MA) delivers remarks during a news conference on the fifth anniversary of the Dodd-Frank Wall Street Reform and Consumer Protection Act at the U.S. Capitol Visitors Center July 21, 2015 in Washington, DC. (Photo by Chip Somodevilla/Getty Images)
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"(at)RealDonaldTrump knows he's a loser. His insecurities are on parade: petty bullying, attacks on women, cheap racism, flagrant narcissism," the Massachusetts Democrat wrote on her campaign's Twitter account on Monday, part of a rapid-fire burst of eight tweets attacking the billionaire television personality.

"But just because (at)realDonaldTrump is a loser everywhere else doesn't mean he'll lose this election," Warren warned her allies.

A week ago, Warren took to Facebook to try stirring up Trump opponents to speak out.

"Donald Trump is a bigger, uglier threat every day that goes by -- and it's time for decent people everywhere -- Republican, Democrat, Independent - to say No More Donald," she wrote.

Trump poked back in an interview with New York Times writer Maureen Dowd in a column that appeared in Sunday's newspaper.

Trump said of Warren's criticism, "I think it's wonderful because the Indians can now partake in the future of the country. She's got about as much Indian blood as I have."

"Her whole life was based on a fraud," he added. "She got into Harvard and all that because she said she was a minority."

During her 2012 election campaign, Warren was criticized after being listed in law school directories as having Native American ancestry.

Trump's campaign did not immediately provide a response to Warren's latest remarks.

The exchange comes with Trump leading the race for convention delegates over two surviving competitors and some GOP leaders trying to head off his nomination, saying he would be defeated and cause losses for GOP congressional candidates.

In her tweets, Warren accused Trump of running failed businesses, cheating people and using bankruptcies to avoid debts.

She said he was "ready to tear apart an America that was built on values like decency, community, and concern for our neighbors." And she wrote, "Many of history's worst authoritarians started out as losers -- and (at)realDonaldTrump is a serious threat."

"The way I see it, it's our job to make sure (at)realDonaldTrump ends this campaign every bit the loser that he started it," Warren tweeted Monday on her campaign account, which has 261,000 followers.

Trump, a prodigious tweeter, has 7 million followers on his account.

Warren has yet to issue an endorsement in the Democratic presidential contest between former Secretary of State Hillary Clinton and Sen. Bernie Sanders, D-Vt.

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