WASHINGTON (Reuters) - Donald Trump will outline a series of incentives on Tuesday to encourage foreign companies to relocate to the United States if he wins the Nov. 5 election, including an offer of federal land, according to a source familiar with his planned remarks.

The Republican presidential candidate is also expected to say during a speech on the economy in Savannah, Georgia that he will personally reach out to foreign firms to push them to bring their operations into the country, said the source, who requested anonymity as the remarks are not yet public.

Companies that refuse such an offer, Trump is set to say, will be hit with tariffs.

Preserving and creating American manufacturing jobs by slapping expansive tariffs on friends and foes alike has become a central theme of Trump's economic message, particularly in the closing months of the race against Vice President Kamala Harris, the Democratic nominee.

While Trump and his allies say trade barriers are necessary to protect U.S. industry, mainstream economists roundly say Trump's proposals would boost consumer inflation.

It is unclear what federal lands would be offered to foreign companies under Trump's plan, or how such an arrangement would work. If land remains in federal hands while foreign companies operate on it, those companies could in theory be exempt from property tax.

Trump is also set to reiterate a pledge to lower corporate tax rates, but only for companies that manufacture domestically. The former president said earlier this month that he would cut the rate to 15% from 21% for domestic manufacturers.

Harris, who polls show is in a tight race with Trump, is set to unveil a suite of new economic proposals in Pennsylvania on Wednesday. Some of those proposals will be broadly aimed at helping Americans build and maintain wealth, Reuters reported.

(Reporting by Gram Slattery, editing by Ross Colvin)