AKRON -- Hillary Clinton slammed Donald Trump on Monday over a new report that the real estate mogul chose to buy steel and aluminum for two of his most recent projects from Chinese manufacturers, instead of American ones.

“Instead of buying his steel and aluminum from American plants here in Ohio and Pennsylvania, instead of supporting hard working families and American jobs, he once again stiffed us,” Clinton said at a campaign event in Akron, Ohio. “He sent that money overseas.”

Clinton asked: “How can he make America great again when he won’t even buy American products?”

Monday marked Clinton’s first trip in a month to battleground Ohio, where her Republican opponent has been able to pull ahead of her in the polls thanks in large part to his support among white, working class voters. Her visit comes just one week before the deadline to register to vote in the state and, in Akron, Clinton vowed to return, acknowledging the tightening race.

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“I need your help,” she said. “Talk to anybody you know here who thinks they might be voting for Trump. I know you know people -- I know you do -- and you’ve got to stage an intervention.”

Earlier Monday in Toledo, where Clinton made a speech on the economy, she seized on a New York Times’ report that showed Trump reported a nearly $1 billion loss on 1995 tax returns, which could have helped him avoid paying federal income tax for up to 18 years.

“What kind of ‘genius’ loses a billion dollars in a single year?” she joked.

A new Quinnipiac poll released on Monday afternoon showed Trump ahead of Clinton in Ohio by 5 points in a four-way race, which is in line with a recent spate of other state polls. The Clinton campaign is mobilizing for a competitive race in Ohio, investing heavily in resources on the ground and on the airwaves, but her aides are looking at the state more as a way to stop Trump than as a must-win for her.

In a memo to donors and supporters last month, Robby Mook, Clinton’s campaign manager, explained why. He wrote that, by the numbers, “Hillary can win just one” of three contested states -- Florida, Ohio or North Carolina -- “and win the presidency.” By comparison, Mook wrote in the memo that Trump can’t win the White House without Ohio.

Clinton’s travel schedule in the last few weeks reflects that strategy; she has campaigned mainly outside the Rust Belt, prioritizing stops to rally her base voters in North Carolina and Florida while high-profile surrogates, including Bill Clinton and Sens. Bernie Sanders and Elizabeth Warren, have hit the road in her place in Ohio. The former President will return to Ohio on Tuesday for a two-day bus tour across Eastern Ohio and the Mahoning Valley, where Trump has been successful in wooing Democrats away from Clinton.

In both Toledo and later in Akron, Clinton made a direct appeal to those blue-collar voters that Trump has zeroed in on, saying her opponent represents the “rigged system” that he has vowed to change.

“I know people want change,” she said. “That’s part of the American, dynamic spirit. We want change. I’ll tell you, one thing that is certain is we’ll have change. But what kind of change?”