"We believe this race will be incredibly intense, so we may not know the election's outcome for several days," campaign chairwoman Jen O'Malley Dillon told reporters.
She added that by the morning of Nov. 6, the campaign expects "the most results" from Wisconsin and additional updates from Pennsylvania and Michigan.
After that, further results are anticipated from Pennsylvania, Arizona, and Nevada. "Be aware that some ballots will continue to be counted over many days," she said.
O'Malley Dillon noted that in Nevada, ballots can be received until Nov. 9, while early counting in Pennsylvania may not start until Nov. 8.
"This means we will continue to see new votes for many days after Election Day, and this is not a sign of fraud; it's just how the process works," Harris emphasized.
US presidential elections
On July 22, all 50 heads of state Democratic Party headquarters backed Kamala Harris as the new presidential candidate.
By August 2, she secured enough delegate votes to officially become the Democratic nominee for president.
A Bloomberg News/Morning Consult poll released on Sept. 26 showed Harris with a narrow lead over Republican nominee Donald Trump in six critical swing states.
However, on October 12, The Hill reported that Trump had improved his chances of victory, while Harris appeared to be losing her lead.
According to a PBS News/NPR/Marist poll, Harris leads Trump by 4% ahead of the election, with 51% of likely voters supporting Harris compared to 47% for Trump.