US Vice President Kamala Harris is racing to lock down support after Joe Biden’s withdrawal from the presidential race – securing millions in donations and support from as far away as Beyonce’s mother.

Harris became the leading candidate to succeed Biden as the presumptive Democratic presidential nominee – and her party’s main hope of defeating Republican Donald Trump – with Biden’s announcement late on Sunday (US time) that he was quitting.

She wasted no time in speaking to leading Democrats to secure their backing for the nomination.

“Her team is fully activated and phones are ringing, emails are blowing up. This thing is rolling,” supporter Jared Huffman, a California Democrat, said on Sunday.

“This has taken off like a rocket ship.”

The campaign dollars were already flooding in for Harris.

The Democratic fundraising platform ActBlue said Sunday night that small-dollar donors raised more than $US46.7 million ($69.8 million) in the first five hours of Harris’ candidacy.

“Grassroots supporters are energised and excited to support her as the Democratic nominee,” the group said on X.

UPDATE: As of 9pm ET, grassroots supporters have raised $46.7 million through ActBlue following Vice President Kamala Harris’ campaign launch. This has been the biggest fundraising day of the 2024 cycle. Small-dollar donors are fired up and ready to take on this election 🔥

— ActBlue (@actblue) July 22, 2024

Harris spoke multiple times with Biden on Sunday, according to people familiar with the conversations – a day after Biden huddled with his closest aides in Rehoboth Beach, Delaware, as he began to conclude that he would end his re-election bid.

About two hours after Biden’s surprise Sunday announcement, Harris released her own statement, making it clear she knew the nomination would not just be handed to her.

“I am honoured to have the president’s endorsement and my intention is to earn and win this nomination,” Harris said.

“Over the past year, I have travelled across the country, talking with Americans about the clear choice in this momentous election. And that is what I will continue to do in the days and weeks ahead.”

There are already signs that Harris may not be alone in the Democratic race.

West Virginia Senator Joe Manchin, who left the party earlier this year to become an independent, is considering re-registering as a Democrat to vie for the nomination, according to Jonathan Kott, a long-time adviser to Manchin.

 

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Harris has also yet to consolidate the party’s top heavyweights behind her.

Former president Bill Clinton and former Secretary of State (and one-time candidate) Hillary Clinton endorsed her even before she had commented on Biden’s decision, but former president Barack Obama held off, merely pledging support behind the eventual party nominee.

Former Speaker Nancy Pelosi – seen as key in Biden’s decision not to run – and Senate Majority Leader Chuck Schumer are also yet to issue public statements of support.

Meanwhile, Republican rival Trump was quick to issue a scathing assessment of Harris.

“Harris will be easier to beat than Joe Biden would have been,” Trump told CNN.

He and his campaign later also attacked Biden and Harris on social media while saying Biden was unfit to continue serving as president.

On Sunday night, Harris issued her first fundraising email that declared: “I am running to be President of the United States.”

“It has been the honour of a lifetime to serve alongside our Commander in Chief, my friend, President Joe Biden – one of the finest public servants we will ever know,” she wrote.

“I am honoured to have his support and endorsement. And I am eager to run on the record of what Joe and I have accomplished together.”

But as she works to consolidate the party behind her, Harris still has her day job – while Biden remains sidelined due to Covid-19.

She is slated to meet Israeli Prime Minister Benjamin Netanyahu during his visit to Washington later this week.

Harris also has a previously scheduled campaign swing to Milwaukee on Tuesday.

Biden’s decision comes less than a month before the Democratic National Convention, where the presidential candidate will be officially nominated.

-with AAP