Harris's decision could be announced at any time before her first public appearance with the vice-presidential nominee on Tuesday in Philadelphia before they started a tour across several battleground states likely to decide the election, the sources said.
Harris closed out her search by interviewing three top candidates - Minnesota Governor Tim Walz, US senator Mark Kelly of Arizona and Pennsylvania Governor Josh Shapiro - at her Naval Observatory residence in Washington on Sunday, the sources said.
The vice-president met Transportation Secretary Pete Buttigieg for 90 minutes on Friday and was also meeting candidates virtually, the sources said.
Kentucky Governor Andy Beshear and Illinois Governor JB Pritzker are the other candidates in contention for the job.
Kamala Harris interviewed contenders including Pennsylvania Governor Josh Shapiro. (AP PHOTO)
Harris's search for a running mate began in earnest just two weeks ago, shortly after President Joe Biden withdrew from the race and endorsed her to replace him.
The choice of a running mate is one of the most consequential decisions of Harris's political career as she hastily pulls together a campaign to challenge Donald Trump in the November 5 election.
Harris's shortlist includes all white men with a record of winning over rural, white or independent voters.
At the weekend, Harris met her vetting team, including former attorney-general Eric Holder, whose law firm scrutinised the finances and background of potential running mates.
Holder and his office made in-depth presentations on each of the finalists, according to multiple sources familiar with the process.
Harris was weighing the decision with her husband, Doug Emhoff, brother-in-law Tony West and a small circle of aides and advisers, the sources said.
The candidates would be informed on Monday night or Tuesday morning whether they were picked, the sources said.
Minnesota Governor Tim Walz was among the finalists in Kamala Harris's search for a running mate. (AP PHOTO)
The Harris campaign also plans a social media announcement featuring the duo, campaign officials familiar with the arrangements told Reuters.
On her battleground states tour, Harris and her new running mate will hit seven cities in five days: Philadelphia, Pennsylvania; Eau Claire, Wisconsin; Detroit, Michigan; Durham, North Carolina; Savannah, Georgia; Phoenix, Arizona; and Las Vegas, Nevada.
They would hold rallies in each location along the tour, which will include college campuses, historically Black universities, union halls and restaurants, a campaign official said.
Republican vice-presidential nominee JD Vance will also make a campaign stop in South Philadelphia on Tuesday.
At the weekend, the Harris campaign launched a program to persuade Republican voters to support the Democrat and showcased endorsements from Republicans including former Trump White House officials Stephanie Grisham and Olivia Troye.
The program - called Republicans for Harris - will hold kick-off events in the battleground states of Arizona, North Carolina and Pennsylvania on Monday.
Republican surrogates will appear at events led by Harris and her yet-to-be-named running mate and combine on-the-ground organising efforts and paid media to reach Republican voters.
with Reuters
