LAS VEGAS (BLOOMBERG) - Michael Bloomberg came under attack from all sides on the Democratic debate stage on Wednesday (Feb 19) as his rivals compared him to United States President Donald Trump for his treatment of women and minorities.

Senator Elizabeth Warren aggressively lashed out at the former New York mayor, whose recent rise in the polls has shaken up the Democratic presidential race, particularly over his attitudes towards women.

"I'd like to talk about who we're running against - a billionaire who calls women fat broads and horse-faced lesbians. And no I'm not talking about Donald Trump, I'm talking about Mayor Bloomberg," Ms Warren said, arguing that the country shouldn't swap "one arrogant billionaire for another".

She called on Mr Bloomberg to release women from non-disclosure agreements signed when they settled complaints against his company citing sexual harassment and a hostile work environment.

Mr Bloomberg said that none of the women who filed complaints against his company accused him "of doing anything other than maybe they didn't like the joke I told".

He reiterated that he will not revoke the non-disclosure agreements. "They signed these agreements and that's what we're going to live with," he said.

Many of the candidates assailed the former New York mayor on the stop-and-frisk policy carried out by the police department when he led the city.

Senator Bernie Sanders, the current front runner in the contest, called the policy an "outrageous" affront to blacks and Latinos that will alienate voters Democrats need to defeat Mr Trump.

Former vice-president Joe Biden, who has lost some of his support from black voters to Mr Bloomberg in recent polls, recalled that the Obama administration sent Justice Department monitors to New York because of the policy.

He called stop-and-frisk "abhorrent" and "a violation of every right people have".

Mr Bloomberg, who made a public apology for the policy a week before he entered the race, said he was "worried about, embarrassed about" how the stop-and-frisk policy turned out.

Ms Warren argued that Mr Bloomberg's apologies have been insufficient and too focused on how the programme looks in retrospect.

"This isn't about how it turned out, this is about what it was designed to do to begin with, it targeted communities of color," she said. "The apology has to start with the intent of the plan as it was put together and the wilful ignorance day by day by day."

Ms Amy Klobuchar and Mr Pete Buttigieg also joined in the attacks on Mr Bloomberg, though Mr Buttigieg targeted Mr Sanders as well. He called them "the two most polarising candidates" in the race.

Mr Bloomberg responded that he's the only candidate who can beat Mr Trump in November and do an effective job as president. He was direct in his criticism of Mr Sanders, who he views as his main competitor for the Democratic nomination.

"I don't think there's any chance of the senator beating President Trump," Mr Bloomberg said. "I know how to take on an arrogant con man like Donald Trump."

Mr Buttigieg and Ms Klobuchar, who are competing as the centrist alternatives to Mr Biden and Mr Bloomberg, engaged in a brief but bitter exchange.

Ms Klobuchar was asked to explain her recent stumble in an interview in which she was asked to give the name of Mexico's president, Andres Manuel Lopez Obrador, and couldn't.

Mr Buttigieg, who correctly answered the question, said her inability to answer the question was evidence that she didn't have the right knowledge and experience to be president.

Ms Klobuchar, who in the past has attacked Mr Buttigieg on his inexperience, responded: "Are you trying to say I'm dumb? Are you mocking me?"

The debate is coming at a pivotal moment for all the candidates. The Nevada caucuses are on Saturday followed a week later by a primary in South Carolina. Mr Bloomberg doesn't appear on a ballot until 14 states and territories vote March 3 on Super Tuesday, including the big delegate prizes of California and Texas.

Many voters were seeing Mr Bloomberg live for the first time instead of in an ad on television or on social media. Those ads, paid for with his personal fortune, have fuelled a rise in polls that has rattled the Democratic nomination race.

Those polling numbers - he was in a tight third place at 14 per cent to Mr Sanders' 32 per cent and Mr Biden's 16 per cent in a Washington Post/ABC News poll released on Wednesday - qualified him to join five of his Democratic rivals for the ninth debate of the primary season, sponsored by NBC and the Nevada Independent.

Mr Bloomberg, 78, served three terms as New York's mayor, but he's untested on a crowded debate stage, something that's become routine for the other candidates.

Mr Sanders, 78, and Mr Buttigieg, 38, are neck-and-neck in the delegate count after the Iowa caucuses and the New Hampshire primary.

But Mr Sanders is poised to pull ahead with the Nevada caucuses, as Mr Buttigieg has yet to gain traction with minority voters, who'll play a much bigger role there and in South Carolina the following week.

Mr Sanders, though, will face questions about whether his progressive policies are too extreme for a general-election campaign. There's rising concern within the party establishment that the self-described democratic socialist won't be able to defeat Mr Trump and could be a drag on Democratic candidates running for lower offices.

Both Mr Biden, 77, and Ms Warren, 70, are attempting to right struggling campaigns.

Ms Warren's fortunes have sunk as Mr Sanders' rose, leaving her with a third-place finish in Iowa and fourth in New Hampshire. Likewise, Mr Biden has tumbled from his perch as front runner as both Mr Buttigieg and Mr Bloomberg made gains.

Mr Biden has promised a first- or second-place finish in Nevada and wants to show his campaign is still viable after disappointing finishes in Iowa and New Hampshire.

Ms Klobuchar, 59, is looking to repeat her performance in the last debate, which served as a springboard to a third-place finish in New Hampshire. But she's lagged in fund-raising and, as a result, the ability to build a national campaign that will be needed to be competitive in the 14-state Super Tuesday round of primaries.

The other billionaire in the race, former hedge fund manager Tom Steyer, did not qualify under the new rules for the first time. He has his best chance to collect delegates in South Carolina, where recent polls show him running in third place behind Mr Biden and Mr Sanders.