Harris had a lead of six percentage points based on unrounded figures - which showed her with support from 46.61% of registered voters while Trump was backed by 40.48%, according to the three-day poll that closed on Monday.

The Democrat's lead was slightly higher than her five-point advantage over Trump in a Reuters/Ipsos poll two weeks ago.

While national surveys including Reuters/Ipsos polls give important signals on the views of the electorate, the state-by-state results of the Electoral College determine the winner, with seven battleground states likely to be decisive. Polls have shown Harris and Trump are neck-and-neck in those battleground states.