Republican Donald Trump took aim at U.S. free trade deals in a speech delivered in Western Pennsylvania Tuesday that painted his likely Democratic rival Hillary Clinton as a champion of the kind of globalization that has pushed manufacturing jobs overseas.

"This wave of globalization has wiped out totally, totally our middle class," said Trump, standing in front of stacks of compressed metal on the floor of Alumisource, a plant that provides aluminum scrap and other raw materials to the aluminum and steel industries.  "It doesn't have to be this way. We can turn it around and we can turn it around fast."

The speech, delivered in the heart of America's struggling rust belt, stressed a central premise of his campaign: that global free trade -- a Republican Party staple for decades -- has hurt American workers because deals have been negotiated poorly. Trump has vowed to bring back manufacturing jobs, in part, by slapping tariffs on goods produced by companies that move manufacturing jobs offshore.

It's a message that he's hoping will continue to resonate with the white, working class voters, who powered his primary campaign.

Trump, in his speech, portrayed Clinton as an agent of a status quo "that worships globalism over Americanism" and criticized her past support for the Trans-Pacific Partnership, which he described as "the deathblow for American manufacturing."

He said the North American Free Trade Agreement, which was signed by Bill Clinton, was a "disaster" and pointed to the Clintons support for normalizing trade relations with China.

He said that, as president, he would dramatically overhaul the way the country approaches trade, threatening to wield new tariffs and taxes to push his way.

"Ladies and gentlemen, It's time to declare our economic independence once again," he said.

He vowed to renegotiate North American Free Trade Agreement to get a better deal "by a lot, not just a little," for American workers -- and threatened to withdraw the U.S. from the deal if his proposals aren't agreed.

"We already have a trade war. And were losing badly," Trump said.

The setting was a change of scenery for the presumptive GOP nominee. It's a change of setting for Trump, who typically favors his own ritzy golf clubs and ballrooms for formal speeches.

Monessen, the sleepy manufacturing city of about 7,500 about an hour south of Pittsburgh, has been especially hard-hit by the decline in steel industry.

The speech comes as Trump, facing sliding poll numbers and a far larger Clinton operation, is working to re-tool his message for the general election. In addition to a slew of new hires, Trump has been delivering a series of prepared speeches aimed at calming the nerves of GOP donors and others concerned about his often combative style.

Clinton's positon on trade has been a frequent attack line for Trump. Clinton announced her opposition to the Pacific trade deal last October, saying it failed to meet her test of providing good jobs, rising wages and protecting national security. She raised specific concerns about a potential for currency manipulation by China and provisions that she said would benefit pharmaceutical companies at the expense of patients.

That marked a striking reversal for the former secretary of state, who promoted the deal in dozens of appearances during Obama's first term. During a 2012 trip to Australia, she called it the "gold standard in trade agreements." Video clips of Clinton talking about the trade deal are stored on YouTube, giving her opponents footage that could be used in television ads to highlight her shifting positions.

Trump heads later to St. Clairsville, Ohio for a rally at the eastern campus of Ohio University. It will be Trump's first visit to the crucial battleground state since he secured enough delegates to become his party's presumptive nominee.

Trump will also stop in Wheeling, West Virginia for an invitation-only fundraiser with coal magnate Robert Murray. Trump has promised to revive the coal industry, while Clinton has emphasized cleaner fuel sources.