Kamala Harris has secured the Democratic US presidential nomination, becoming the first woman of colour at the top of major party ticket.

The US vice-president officially claimed the nomination following a five-day online voting process, receiving nearly 4600 votes, which it said was 99 per cent of participating delegates.

The party did not release a precise number of votes that were cast for “present” or the state-by-state breakdown of “present” votes, though it did release state-by-state numbers for Harris.

Harris had already secured the majority of votes needed to claim the nomination by Friday afternoon, DNC Chair Jaime Harrison announced in a live video presentation that day to mark the milestone, but the result was not official until after the voting period closed at 6pm on Monday.

Harris will introduce her new running mate at a rally on Tuesday evening in Philadelphia — but with the event mere hours away, her choice remains a mystery.

In recent days, she has zeroed in on a trio of potential finalists: Pennsylvania Governor Josh Shapiro, Arizona Senator Mark Kelly and Minnesota Governor Tim Walz, but decisions beyond that aren’t yet publicly known.

Harris’s campaign planned to make the announcement via video message before the rally, though the exact timing remained unclear, according to a person involved in the planning who spoke on the condition of anonymity to detail discussions occurring behind closed doors.

Doing so would be similar to how then-candidate Joe Biden revealed Harris as his vice-presidential choice during the pandemic-marred presidential race of 2020.

It will mark yet another major milestone in the barely two weeks since the vice-president moved to take over the top of the Democratic ticket heading into November’s election.

She has been scrambling to build out a campaign since then, and to breathe new life into the Democratic race against Republican Donald Trump.

Harris, second gentleman Doug Emhoff and her number two pick are set to appear together for an evening rally in Philadelphia, recalling a joint 2020 appearance by Biden and Harris in Wilmington, Delaware.

Likewise, in 2016, newly selected running mate Senator Tim Kaine of Virginia appeared with Hillary Clinton in Miami.

After Tuesday’s trip to Pennsylvania, Harris and her running mate will spend the next five days flying around the country, touring critical battleground states.

They’ll visit Eau Claire, Wisconsin, and Detroit on Wednesday. But a planned stop in Savannah, Georgia, was postponed due to Tropical Storm Debby ‘s effects, and rain associated with it could also upend a scheduled stop in Durham, North Carolina.

Later in the week, Harris and her running mate will head to Phoenix and Las Vegas.

That the schedule was set before her pick was identified recalls a cliffhanger-like scenario that Trump created by holding off on making his choice of vice presidential hopeful, Ohio Senator JD Vance, until last month’s Republican National Convention was under way in Milwaukee.

– AAP