San Francisco's former mayor Willie Brown has dismissed as "fiction" Donald Trump's story that they once endured a scary helicopter trip together.

The former president said on Thursday that he and Mr Brown "went down" in a helicopter together and Mr Brown was "a little concerned".

"We thought maybe this was the end," Trump said. "We were in a helicopter... and there was an emergency landing. This was not a pleasant landing."

Mr Brown, 90, told US media he had never shared a helicopter with Trump, adding: "I don't think I'd want to ride on the same helicopter with him".

Trump, 78, appeared to be confusing Mr Brown with Jerry Brown, California's former governor, with whom he shared a helicopter ride in 2018 to visit the aftermath of the Paradise wildfires. Gavin Newsom, the current state governor, was also on the flight.

Both men told US media there was no emergency landing or danger. "I call complete BS," Mr Newsom told The New York Times.

Trump told his story in response to a question about Willie Brown's relationship with Kamala Harris, 59, in the mid-1990s while she was a California prosecutor.

Trump was asked whether he thought the relationship played a role in Ms Harris's career journey.

"Well, I know Willie Brown very well," Trump said, before speaking of the flight and claiming the former mayor had told him "terrible things" about Ms Harris.

"He had a big part in what happened with Kamala," Trump said.

The former mayor also denied this.

"That's so far-fetched, it's unbelievable," hetoldlocal TV station KRON. "I could not envision thinking of Kamala Harris in any negative way.

"She's a good friend a long time ago, absolutely beautiful woman, smart as all hell, very successful, electorally speaking.

"He was doing what Donald does best, his creative fiction."

A spokesperson for Jerry Brown also told US media that the former governor did not discuss Ms Harris on the helicopter flight in 2018.

Trump's remarks at an hour-long news conference at his Mar-a-Lago estate come as a recent national poll shows Ms Harris is beating him among likely voters.

The two have visited a number of battleground states this week alongside their vice-presidential candidates to speak to voters. (Courtesy, excluding headline, BBC)