Kamala Harris has conducted the first solo interview of her White House campaign since she took up the baton as the Democrats' presidential candidate nearly two months ago.

The US vice-president sat down with a local ABC News station in the key swing state of Pennsylvania to discuss the economy, a political vulnerability, and gun control.

Reacting to the interview, her Republican rival, Donald Trump, said she "had a very hard time yesterday answering the simplest of questions".

Harris and Trump are in a dead heat in Pennsylvania and other battleground states ahead of November's White House election, according to opinion polls.

Last month Harris proposed the "first-ever federal ban on price gouging on food", though she did not mention that idea in Friday’s interview. It had provoked criticism from economists and business groups, and Trump likened it to Soviet-style price controls.

Harris also told the local ABC station on Friday that she supports constitutional gun rights, but wants to see semi-automatic weapons prohibited.

"I feel very strongly that it is consistent with the Second Amendment and your right to own a gun to also say we need an assault weapons ban," she said. "They're literally tools of war."

Harris went on to take a swing at Trump, saying the American people need someone to bring the country together, unlike her rival, who she said was "trying to have us point our fingers at each other".

She was also asked how she differed from the current US president, who suspended his campaign on 21 July and endorsed her. Harris repeated a line from the debate, saying she is "obviously not Joe Biden".

She also said she would "offer a new generation of leadership".

Trump posted on his social media platform Truth Social on Saturday morning that the interview was “a world salad, a real mess!”

Harris’ campaign was boosted this week when opinion polls suggested she won her first debate on Tuesday with Trump. The Republican has since said he will not debate her again, claiming he was the winner.

Amid calls for her to grant more media access, Harris last month sat down on CNN for her first interview since becoming the nominee, joined by her running mate Tim Walz.