Republican presidential nominee Donald Trump will lay out on Saturday what he would do in the first 100 days of his administration should he win the Nov. 8 election.

Trump’s outline - which he will deliver in a speech in the historic town of Gettysburg, Pennsylvania - will cover his plans for boosting Americans' economic and physical security and contrast them with those of Democrat Hillary Clinton, campaign aides told reporters on Friday.

Clinton published a book of her own policy ideas earlier this year.

Trump is trailing Clinton in most polls - although he has narrowed the gap according to a Reuters/Ipsos poll released on Friday - and has less than three weeks to catch up.

Much of the campaign in recent weeks has focused on allegations that he made improper advances to women over decades, something he denies.

It is also being dominated by Trump's accusation that the election is "rigged" and that he may not accept the result.

Trump aides said Gettysburg, the site of a major Civil War battle and Republican President Abraham Lincoln’s famous address, was a fitting place for Trump to lay out a positive vision for the future of his party, which has suffered a schism between his supporters and the party's establishment.

Trump has planted some new policy details in recent speeches as he seeks to shift attention away from the recent controversies.

In the past week, for example, he laid out ethics rules to shut the “revolving door” between government and lobbying and proposed term limits for members of Congress.

Trump's aides said he would unveil additional new policy details Saturday. They would not elaborate.