Vice President Kamala Harris has defended shifting away from some of her more liberal positions in her first major television interview of her presidential campaign, but insisted her “values have not changed” even as she is “seeking consensus”.

Sitting with her running mate Minnesota Governor Tim Walz, Harris on Thursday was asked about changes in her policies over the years, specifically her reversals on fracking and decriminalizing illegal border crossings.

“I think the most important and most significant aspect of my policy perspective and decisions is my values have not changed,” Harris replied.

The interview with CNN's Dana Bash gave Harris a chance to try to quell criticism that she has eschewed uncontrolled environments while also giving her a fresh platform to define her campaign and test her political mettle ahead of an upcoming debate with former President Donald Trump set for Sept 10. But it also carried risk as her team tries to build on momentum from the ticket shakeup following Joe Biden's exit and last week's Democratic National Convention.

“First and foremost, one of my highest priorities is to do what we can to strengthen and support the middle class," Harris said. "When I look at the aspirations, the goals, the ambitions of the American people, I think that people are ready for a new way forward."

The CNN interview was taped at 1:45 pm Thursday at Kim's Cafe, a local Black-owned restaurant in Savannah, Georgia, and aired in the evening.

Harris also brushed off Trump's questioning of her racial identity after the former president said she “happened to turn Black”. Harris, who is of Black and South Asian heritage, said it was the “same old, tired playbook”.

"Next question."

She also said she'd name a Republican to serve in her Cabinet if she were elected, though she didn't have a name in mind.

Joint interviews during an election year are a fixture in politics; Biden and Harris, Trump and Mike Pence, Barack Obama and Biden — all did them at a similar point in the race. The difference is those other candidates had all done solo interviews, too. Harris hasn't yet done an in-depth interview since she became her party's standard bearer five weeks ago, though she did sit for several while she was still Biden's running mate.

Harris and Walz are still introducing themselves to voters, unlike Trump and Biden, of whom people had near-universal awareness and opinion.

Harris said serving with Biden was “one of the greatest honours of my career,” as she recounted the moment he called to tell her he was stepping down and would support her.

During her time as vice president, Harris has done on-camera and print interviews with The Associated Press and many other outlets, a much more frequent pace than the president — except for Biden's late-stage media blitz following his disastrous debate performance that touched off the end of his campaign.

Harris' lack of media access over the past month has become one of Republicans' key attack lines. The Trump campaign has kept a tally of the days she has gone by as a candidate without giving an interview and have suggested she needs a “babysitter” and that's why Walz will be there.

“I just saw Comrade Kamala Harris' answer to a very weakly-phrased question, a question that was put in more as a matter of defence than curiosity, but her answer rambled incoherently, and declared her values haven't changed,'” Trump posted online.

Trump has largely steered toward conservative media outlets when granting interviews, though he has held more open press conferences in recent weeks as he sought to reclaim the spotlight that Harris' elevation had claimed.

Harris and Walz went out on a two-day bus tour through southeast Georgia that culminated with an evening rally in Savannah. Harris campaign officials believe that in order to win the state over Trump in November, she must make inroads in GOP strongholds across the state.

Democrats' enthusiasm about their vote in November has surged over the past few months, according to polling from Gallup. About 8 in 10 Democrats now say they are more enthusiastic than usual about voting, compared with 55% in March.

This gives them an enthusiasm edge they did not have earlier this year. Republicans' enthusiasm has increased by much less over the same period, and about two-thirds of Republicans now say they are more enthusiastic than usual about voting.

But at a packed arena on Thursday, Harris cast her nascent campaign as the underdog and encouraged the crowd to work hard to elect her in November.

“We're here to speak truth and one of the things that we know is that this is going to be a tight race to the end,” she said.

Harris went through a list of Democratic concerns: that Trump will further restrict women's rights after he appointed three judges to the US Supreme Court who helped overturn Roe, that he'd repeal the Affordable Care Act, and that given new immunity powers granted presidents by the US Supreme Court, “imagine Donald Trump with no guard rails.”

Her rally was briefly disrupted by demonstrators who were protesting the US involvement in the Israel-Hamas war.

The campaign wants the events to motivate voters in GOP-leaning areas who don't traditionally see the candidates, and hopes that the engagements drive viral moments that cut through crowded media coverage to reach voters across the country.

Harris has another campaign blitz on Labour Day with Biden in Detroit and Pittsburgh with the election rapidly approaching. The first mail ballots get sent to voters in just two weeks.