Both US President Donald Trump and Democratic challenger Joe Biden will commemorate the 19th anniversary of the September 11 attacks in rural Pennsylvania where one of the hijacked planes crashed in a field, the White House and Biden's campaign say.
It was not immediately clear whether their visits to the memorial in Shanksville will overlap.
But it probably will be the closest that the candidates have been to one another in months.
The National Park Service, which co-hosts the annual memorial event, is planning an abbreviated ceremony this year to minimise the spread of the coronavirus.
The agency plans a 20-minute "Moment of Remembrance" set to begin at 9.45am local time without a keynote speaker or musical guests.
The name of each passenger and crew member from Flight 93 will be read aloud with the ringing of the "Bells of Remembrance," according to the agency's website.
A White House spokesman, Judd Deere, said the president and first lady Melania Trump would visit the site "to honour and remember the lives lost" on September 11, 2001.
In 2016, Trump and Democratic president nominee Hillary Clinton both spent September 11 in New York and both visited the Ground Zero memorial in lower Manhattan.
The day ended up being a significant one on the campaign after Clinton abruptly left the ceremony, complaining she was overheated, and was captured on video struggling to step into a van.
The Flight 93 National Memorial marks the spot in rural Pennsylvania where the hijacked flight crashed, killing all 40 people on board.
Australian Associated Press
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