Republican presidential nominee Donald Trump and his Democratic rival Kamala Harris will attend a debate on September 10, the ABC network in the United States has confirmed.

In a news conference at his Palm Beach, Florida, residence on Thursday, Trump said he wanted additional debates on September 4 and 25 as well.

He did not detail specific terms, including whether there would be an audience, and it was not immediately clear whether his campaign had made a proposal to Harris’s camp.

The Harris campaign did not immediately comment.

Trump had previously suggested he might back out of the ABC debate, which was scheduled before Vice President Harris replaced President Joe Biden as the Democratic presidential candidate less than three weeks ago, upending the contest.

The news conference was Trump’s first public appearance since Harris selected Minnesota Governor Tim Walz as her running mate on Tuesday.

ABC News will host qualifying presidential candidates to debate on September 10 on @ABC.

Vice President Harris and former President Trump have both confirmed they will attend the ABC debate. https://t.co/DEBOGC2ovO pic.twitter.com/t0KAWpcYOY

— ABC News (@ABC) August 8, 2024

Harris and Walz have headlined rallies in the battleground states of Pennsylvania, Michigan and Wisconsin this week, drawing tens of thousands of attendees in a new sign of how her late entry into the race has energised Democrats.

Her rapid rise has sent Trump’s team scrambling to recalibrate their strategy and messaging. Opinion polls suggest Harris has erased – or at least shrunk – the lead Trump had built over Biden.

Democrats have also raked in hundreds of millions of dollars from voters and big donors in a matter of weeks.

Asked on Thursday how he has altered his approach to the new challenge from Harris, Trump insisted he has not done so.

In a question-and-answer session with reporters that stretched longer than an hour, Trump moved from topic to topic, claiming Harris and Walz were weak candidates who were already dropping in the polls.

Despite that, he lamented that he would not be able to face Biden in the election, suggesting that the president was a victim of an unconstitutional plot to dislodge him from atop the Democratic ticket.

Biden, 81, dropped his faltering re-election bid under pressure from fellow Democrats worried about his chances of victory in the November 5 election after a disastrous debate performance against Trump.

Reporting from Washington, DC, Al Jazeera’s Rob Reynolds said Trump has been attacking Harris’s intelligence while pushing on with his usual anti-immigration rhetoric.

“There were certainly a lot of familiar sort of rancorous remarks in this press conference about crowd size,” Reynolds said. “The Republican candidate Donald Trump seemed to get very, very upset when there was some suggestion that Kamla Harris was drawing large crowds. So he went on an extended riff about that.”

Echoing a recent criticism from his campaign, Trump criticised Harris on Thursday for not doing a news interview since launching her campaign.

“She can’t do an interview. She’s barely competent,” Trump said, later again calling her “nasty”, a go-to line that he often uses to disparage female critics.

Trump has conducted a steady stream of media interviews, though many are usually with friendly, right-leaning outlets and reporters. On Wednesday, he called into the Fox & Friends morning programme and took questions from the hosts.

Harris and Walz were meeting with autoworkers in Detroit on Thursday, following the United Auto Workers union’s endorsement of their candidacy, as part of a push to mobilise blue-collar workers in key battleground states.

The Harris campaign cancelled events on Thursday in North Carolina and on Friday in Georgia, where Tropical Storm Debby is bringing heavy rain and dangerous flooding. The Democrats will head to Arizona and Nevada later this week, visiting two more swing states likely to play a key role in the election.

Trump’s running mate, Senator JD Vance of Ohio, also cancelled campaign events in North Carolina on Thursday due to the storm. He has spent the last few days trailing Harris and Walz around the country, an unusual move intended to provide a “contrast”, he told reporters on Wednesday.