Ms. Harris campaigned with Mr. Obama, attracting black voters in the battleground state.

"We all know that we have an opportunity to turn the page, to leave behind the fear and division that has dominated our politics for a decade because of Donald Trump. Go vote early," Vice President Kamala Harris told thousands of supporters in Clarkston, Georgia on October 24.

The audience at the rally was predominantly black, a key constituency for Harris if she is to win this battleground state. More than 29 million Americans, including more than 2.3 million in Georgia, have already cast their ballots early.

Ms Harris also highlighted her middle-class background, contrasting herself with a billionaire like Republican candidate Donald Trump, and said she would prioritize fighting inflation if she became president.

"We're going to build a future where the cost of living comes down. That's going to be my focus every day as president of the United States," she said.

Joining Harris at the Clarkston rally, former President Barack Obama attacked Trump, saying his successor only cared about himself. He also questioned Trump's ability to do the job and mocked the Republican candidate's "messy" speeches.

“We don’t need four years of leadership from a wannabe kingmaker who goes around punishing his opponents,” said Obama, who campaigned for Harris in several battleground states.

He also implied that Trump was acting like a "dotard." Referring to Trump's recent appearance at McDonald's and mocking Harris, Obama noted that the vice president actually used to work at the fast-food chain.

"She worked at McDonald's to pay her way through college," Obama said, rejecting Trump's claim that Harris had never worked at a McDonald's restaurant.

Harris' campaign said about 20,000 people attended the rally, making it her largest campaign event yet, surpassing the 17,000 people who attended in Greensboro, North Carolina, earlier in September.

Many people sat for hours to listen to Harris and Obama speak. However, while the Democratic candidate spoke, some people left early, leaving empty spaces in the audience.

This is the first time Harris and Obama have campaigned together. Obama’s wife, Michelle, will join the vice president in the battleground state of Michigan on October 26. The Obamas spoke in support of Harris at the Democratic National Convention in August.

The latest polls in Georgia show Mr. Trump with a small lead, but Harris campaign officials remain confident about the state. President Biden won Georgia unexpectedly in 2020, and Democrats won two Senate seats there, giving them control of both chambers of Congress for the first half of Biden’s term.

Harris’s campaign is ramping up its celebrity rallies to gain an advantage over Trump. Rock legend Bruce Springsteen, actor Samuel L. Jackson and director Spike Lee are joining her in Clarkston, while singer Beyonce will join the vice president in Texas on October 25.