Donald Trump provided a vivid illustration of the difference between the Trump who delivers prepared policy speeches and the one who conducts free-wheeling political rallies — the latter one uses terms like "rape," repeatedly.

"The Trans-Pacific Partnership is another disaster done and pushed by special interests who want to rape our country," Trump told backers at a college in Ohio while criticising the proposed trade deal involving the United States and Pacific Rim nations.

"Just a continuing rape of our country," Trump added.

Hours earlier, in a prepared speech at a aluminum plant in western Pennsylvania, Trump used more restrained language to attack the Trans-Pacific Partnership, saying the proposed trade deal "would be the death blow for American manufacturing."

Trump's later use of the term "rape" brought him criticism in social media, especially amid reports that the campaign is talking to former boxer and convicted rapist Mike Tyson about speaking at next month's Republican convention in Cleveland.

"Trump calling TPP 'rape of our country' as he recruits actual convicted rapist for his convention," tweeted Republican strategist Ryan Williams, who worked on Mitt Romney's presidential candidate four years ago.

Ben Ray, communications director for the pro-Democratic group American Bridge 21st Century, said Trump's language gives the lie to the idea that he is "pivoting" toward a more presidential demeanor.

"Trump needs to learn that rape is never an appropriate metaphor," Ray said.

Trump's rhetoric is harsher than previous nominees

Trump aides have said that their candidate will appear in a variety of settings for the general election, including set policy speeches that are more presidential in nature. He will also do the mass rallies that fueled his Republican nomination campaign, and allow him to be more outspoken — and outrageous, in the view of critics.

In his indictment of the TPP during his appearance in Ohio, Trump acknowledged the weight of the term rape.

"That's what it is, too," the Republican presidential candidate said. "It's a harsh word — it's a rape of our country. This is done by wealthy people that want to take advantage of us and that want to sign another partnership."