Money and support is flowing in for the top pick to take on Donald Trump in the US presidential election.

Joe Biden is endorsing Vice President Kamala Harris after abruptly announcing he's quitting the race.

Endorsements from top Democrats are mounting, with more than $50 million already raised for Harris.

Guardian Washington correspondent David Smith says it's given the Democrats a shot in the arm.

"They were bitterly divided over Joe Biden and dithering and listless, money was drying up - but now it seems to be rallying around Kamala Harris as the nominee."

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