Trump attacks US VP Harris, but silent on running mate

Speaking on Tuesday at his golf club in Doral, Florida, Trump stayed quiet on his planned choice for his running mate, although he name-checked Florida Senator Marco Rubio, who was in attendance and is a leading contender for the role, multiple times.

Taking the stage nearly an hour late on a hot night, Trump blasted the 81-year-old Biden about his shaky debate performance on June 27, which prompted worries about his mental fitness for office and calls from some Democrats for him to step aside.

Biden said he had a bad night and that he will not drop out of the presidential race.

In a mocking tone, Trump called Biden's choice of Harris, the first Black and woman vice president, his "one brilliant decision," implying that she was so inept that Democrats were reluctant to replace Biden with her on the top of the ticket.

"It was an insurance policy, maybe the best insurance policy I've ever seen," Trump told the thousands of supporters in attendance.

"If Joe had picked someone even halfway competent, they would have bounced him from office years ago."

Trump also accused Harris, a former US Senator and California attorney-general, of working with other Democrats on covering up Biden's alleged mental acuity issues. Biden has said he has the stamina and mental sharpness to do the job.

Trump also said Harris' record would hurt her electoral chances, the latest sign that he and his Republican allies are starting an all-out assault on Harris to prepare for Biden possibly ending his re-election bid.

"I don't think Kamala Harris's California socialism is going to go down well with the people of Doral, the people of Miami or the people of Florida. Because in Florida we don't like socialism, we want our freedom," Trump said.

The Biden campaign accused Trump of lying about Harris, and said he was trying to deflect from growing attention paid to Project 2025, a conservative group's controversial plans to remake the presidency should Trump win the November 5 election.

"Trump's bizarre and unhinged rants won't stop Vice President Harris from defending the Biden-Harris record and prosecuting the case against Donald Trump's extreme record," Biden campaign spokesperson Ammar Moussa said.

Seemingly joking, Trump challenged Biden to another debate, saying that it should be "man to man, no moderators, no holds barred," and to 18 holes of golf - a reference to their argument during the debate over who was better at the sport.

"It will be among the most watched sporting events in history, maybe bigger than the Ryder Cup or even the Masters," Trump said, adding that he would give Biden 20 strokes.

Calling the prosecutions against him politically motivated, Trump said he had "great respect for the courage" shown by the conservative justices who ruled in his favour. "They have great intellect and great insight, incredible insight," he said.

On Saturday, the former president will travel to Pennsylvania for an afternoon rally in Butler, just outside of Pittsburgh, where the focus will be on any hint - or announcement - about whom he will pick as vice president.

Rubio, Ohio Senator J.D. Vance and North Dakota Governor Doug Burgum are seen as the leading contenders to join Trump on the Republican ticket. Trump said this week that he would likely make a decision "a little before" or during the Republican Party's national convention, which kicks off on July 15.

Australian Associated Press