"You cannot beat Trump with the same old,same old kind of politics,"Sanders said.

The results suggest former New York City mayor Michael Bloomberg,whospent hundreds of millions of dollars on political advertising in the Super Tuesday states,got a poor return on the unprecedented investment.

Bloomberg failed to win a majority of delegates in any state,though he did carry the tiny territory of American Samoa.

He returned to New York after the results started coming in,and on Wednesday announced he wasdropping out of the race.

The billionaire businessman appeared to have no viable path to the party's nomination,and neither does Elizabeth Warren who finished third in her home state of Massachusetts.

A third of total delegates to the Democratic Party's convention in July were up for grabs on Tuesday,and it will take several days for all the votes to be counted.

Biden started the night strongly by winning North Carolina and Virginia,which had the third and fourth highest numbers of delegates on offer.

As well southern states such as Oklahoma and Tennessee,he picked up surprise victories in Massachusetts and Minnesota where the electorate is more progressive.

Biden had not even campaigned in those states during the campaign,reflecting the assumption he had no hope of winning there.

"Amazing night no one would have predicted even days ago,"David Axelrod,Barack Obama's former chief strategist,wrote on Twitter."We expected a surge. We got a tsunami."

The former vice-president finished in a poor fourth and fifth placed finish in the early voting states of Iowa and New Hampshire,denting his image as the Democrat best-placed to defeat Donald Trump in November.

But his blow-out win in South Carolina cemented him as the leading moderate in the race,and prompted centre-left rivals Pete Buttigieg and Amy Klobuchar to drop out of the contest.

Buttigieg and Klobuchar both speedily endorsed Biden,sending a strong signal to moderate voters to fall in behind the 77-year old.

Biden won overwhelming support from African American and older voters,as well as college-educated white voters in the suburbs.

Sanders continues to perform better among younger progressives,as well as Hispanics.