COMMERCE CITY, Colo. -- Hillary Clinton is criticizing Donald Trump's use of outsourcing at his companies, part of an effort to undercut the business record that has formed the basis of his presidential pitch.

"What kind of man does business by hurting other people? I am just so determined that we are not going to let him do to America what he has done to small business," she told several thousand people gathered at in a high school gymnasium on Wednesday afternoon.

Clinton highlighted Trump's use of outsourcing to manufacture some of his branded products, arguing he's profited from the same foreign labour he now blames for killing U.S. jobs. Most of Trump's branded neckties, shirts and suits are made abroad, in China and Bangladesh, as are the bulk of the products sold by his daughter, Ivanka.

Even his campaign hats, which say they are "Made in the USA," are not entirely made domestically, according to an Associated Press analysis.

"He said: 'Well, we don't make that stuff in America. I'm here to tell you Donald, you're wrong," said Clinton. "I know he's wrong because I've been collecting information and visiting places that actually do make these things in America."

Clinton touted a new website set up by her campaign that provides information on places in the United States that are making ties, suits, furniture and barware.

Before her campaign rally, Clinton visited a Denver tie company that employs a staff of largely refugee workers to manufacture ties and scarves.

"I wish Donald Trump could meet with all of you and see what you are making here," Clinton told the workers. "If he wants to make America great again, he should start by making things in America -- and there's a lot he could learn by coming here."

Clinton's pitch is aimed at cutting into Trump's support among white working class voters drawn to his anti-trade, anti-illegal immigration message.

Her aides believe offsetting some of their expected losses with that group, along with a broad coalition of minority, women and younger voters, could be her path to victory in November.

Clinton also hit Trump for his criticism of the Khan family, who delivered a speech attacking Trump at the Democratic national convention last week. Their son, a Muslim-American Army Captain, was killed by a 2004 suicide bomb in Iraq.

"There is no doubt in my mind that Donald Trump is unqualified to be president and unfit to be commander-in-chief," she said.

Clinton is headed to fundraisers in the Denver area this evening before a campaign event in Las Vegas on Thursday. Colorado and Nevada are among the top battleground states in the fall election and Clinton is using the events to point to a voter mobilization push under way by the campaign aiming to register more than 3 million voters and have them commit to vote in the election.