US Democratic presidential candidate Joe Biden has named Senator Kamala Harris as his running mate - the first black woman and Asian American in the role.
Once a rival for the top job, the California senator of Indian-Jamaican heritage had long been considered the front-runner for the number two slot.
The former California attorney general has been urging police reform amid nationwide anti-racism protests, reports BBC.
Biden will face US President Donald Trump in the election on November 3.
At a White House news conference on Tuesday, Trump, a Republican, described Harris as "my number one draft pick".
Harris will debate Trump's running mate, Vice-President Mike Pence, on October 7 in Salt Lake City, Utah.
Only two other women have been nominated as vice-presidential candidates - Sarah Palin by the Republican party in 2008 and Geraldine Ferraro by the Democrats in 1984. Neither ended up on the winning ticket.
A woman of colour has never been appointed to a presidential ticket by either of the two main American political parties. No woman has won the US presidency either.
Biden tweeted that he had "the great honour" to name Harris as his number two.
He described her as "a fearless fighter for the little guy, and one of the country's finest public servants".
He noted how she had worked closely with his late son, Beau, when she was California's attorney genera, B "I watched as they took on the big banks, lifted up working people, and protected women and kids from abuse," he tweeted.
"I was proud then, and I'm proud now to have her as my partner in this campaign."
Harris later tweeted that Biden "can unify the American people because he's spent his life fighting for us. And as president, he'll build an America that lives up to our ideals.
"I'm honored to join him as our party's nominee for Vice President, and do what it takes to make him our Commander-in-Chief."
The campaign announced that Biden and Harris will deliver remarks in Wilmington, Delaware, on Wednesday afternoon on "working together to restore the soul of the nation and fight for working families to move the country forward".
Biden pledged in March to name a woman on the ticket. He had faced mounting calls to pick a black woman in recent months as the nation was convulsed by social unrest over police brutality against African Americans, a key voting bloc to the Democratic Party.
Who is Kamala Harris?
Harris, 55, dropped out of the presidential race in December after failing in her bid to win the Democratic nomination.
She repeatedly clashed with Biden during the primary election debates, most notably criticising his praise for the "civil" working relationship he had with former senators who favoured racial segregation.
The Democrat was born in Oakland, California, to two immigrant parents: an Indian-born mother and Jamaican-born father.
She went on to attend Howard University, one of the nation's preeminent historically black colleges and universities. She has described her time there as among the most formative experiences of her life.
Harris says she's always been comfortable with her identity and simply describes herself as "an American".
In 2019, she told the Washington Post that politicians should not have to fit into compartments because of their colour or background.
"My point was: I am who I am. I'm good with it. You might need to figure it out, but I'm fine with it," she said.
Meanwhile, US President Trump told reporters:
"She's a person that's told many, many stories that weren't true."
He added: "She did very, very poorly in the primaries, as you know, she was expected to do well and she ended up right around 2%. So I was a little surprised that he picked her."
Trump also said Ms Harris was "very, very nasty" and "horrible" to Mr Biden during the Democratic primary debates.
"She was very disrespectful to Joe Biden and it's hard to pick somebody that's that disrespectful," he said.
The Trump campaign said the choice of running mate was proof that Mr Biden is "an empty shell being filled with the extreme agenda of the radicals on the left".