Sen. Elizabeth Warren bashed GOP front-runner Donald Trump in a series of tweets on Monday, calling the billionaire businessman "a loser" whose rise in politics poses a "serious threat" to America's future.

In an eight-tweet barrage, the Massachusetts Democrat and progressive icon not only used Trump's favorite insult against him, she also attacked his business acumen and implored her supporters to help defeat him.

Let’s be honest - @realDonaldTrump is a loser. Count all his failed businesses. See how he cheated people w/ scams like Trump U. — Elizabeth Warren (@elizabethforma) March 21, 2016

Warren — who's made a name for herself in Congress as an anti-Wall Street and anti-corporate greed crusader — went on to attack Trump's business tactics.

See how @realDonaldTrump kept his father’s empire afloat using strategic corporate bankruptcies to skip out on debt. — Elizabeth Warren (@elizabethforma) March 21, 2016

Listen to experts who say @realDonaldTrump might have more money today if he’d put his inheritance in an index fund & left it alone. — Elizabeth Warren (@elizabethforma) March 21, 2016

And she called him out for being narcissist, sexist and a racist "bully."

.@RealDonaldTrump knows he’s a loser. His insecurities are on parade: petty bullying, attacks on women, cheap racism, flagrant narcissism. — Elizabeth Warren (@elizabethforma) March 21, 2016

But she warned her nearly 260,000 followers that while Trump is a "loser," he could still win the election, which she said should be a concern for those who do not take him seriously.

But just because @realDonaldTrump is a loser everywhere else doesn’t mean he’ll lose this election. — Elizabeth Warren (@elizabethforma) March 21, 2016

.@RealDonaldTrump stands ready to tear apart an America that was built on values like decency, community, and concern for our neighbors. — Elizabeth Warren (@elizabethforma) March 21, 2016

In fact, Warren said many of the world's authoritarian leaders started out the same way Trump has risen in America.

Many of history’s worst authoritarians started out as losers – and @realDonaldTrump is a serious threat. — Elizabeth Warren (@elizabethforma) March 21, 2016

And she called upon her supporters to help defeat Trump in 2016.

The way I see it, it’s our job to make sure @realDonaldTrump ends this campaign every bit the loser that he started it. — Elizabeth Warren (@elizabethforma) March 21, 2016

When asked for a response Monday to Warren's rant, Trump was dismissive, calling Warren "the Indian." Trump's comments likely refer to reports that Warren identified herself as Native American when she was a professor at Harvard Law School — despite little evidence proving her heritage.

"The Indian? You mean the Indian?" Trump says of Warren, who hit him on Twitter. — Maggie Haberman (@maggieNYT) March 21, 2016

Warren's Twitter tirade against Trump came on the same day Democratic presidential front-runner Hillary Clinton unleashed similar attacks on Trump in a speech to pro-Israel advocates in Washington.

Clinton has turned her fire to Trump in recent days, after she amassed a nearly insurmountable delegate lead in her primary race against Sen. Bernie Sanders.

Some Democrats fear Sanders supporters, unmoved by Clinton's candidacy, could fail to vote or end up casting their vote for Trump.

Warren has not yet made an endorsement in the Democratic primary.

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