The polling data showed Trump's argument that the Nov 8 election is "rigged" against him has resonated with members of his party.

"Remember folks, it's a rigged system," Trump told a Pennsylvania rally on Friday. "That's why you've got to get out and vote, you've got to watch. Because this system is totally rigged."

Clinton led Trump 44 percent to 40 percent, according to the Oct 14-20 Reuters/Ipsos poll, a 4-point lead. That compared with 44 percent for Clinton and 37 percent for Trump in the Oct 7-13 poll released last week.

An average of national opinion polls by RealClearPolitics shows Clinton 6.2 percentage points ahead at 48.1 percent support to Trump's 41.9 percent.

Trump is slated to give a speech Saturday in Gettysburg, Pennsylvania, best known as the site of a decisive Civil War battle and cemetery, and the place where Republican President Abraham Lincoln delivered his famous address.