AFL-CIO President Richard Trumka devoted most of his speech on Wednesday at the union federation's 60th Annual Constitutional Convention in Nevada to convincing working-class voters that Donald Trump is "profoundly unfit" to be commander in chief.

"I can't let another moment pass without addressing Donald Trump. Where do I even start?" Trumka said about halfway through his remarks in Reno.

"In just the last month, he dishonored the memory of a fallen hero by criticizing a Gold Star family. He said he always wanted a Purple Heart. He called President Obama the founder of [the Islamic State]. He said the best way for working women to deal with sexual harassment is either 'be strong' or find another job [and] he called for 'extreme vetting' of immigrants," he told an audience of union leaders and workers in the Silver State.

Trumka, who is directing the AFL-CIO's crusade against Trump in Rust Belt states like Ohio and Pennsylvania, said the Republican presidential nominee is "dangerous" and treats working-class voters like "second-class citizens."

"A recent study showed he tells a whopper every five minutes. Don't believe a thing he says," Trumka advised. "He pretends to love our cause, but he's a fraud."

While Trump has spent much of his general election campaign appealing to blue-collar workers who have lost their jobs to overseas outsourcing, his construction projects and hotels have been hot spot for union busting, Trumka charged.

"First, Trump hired a union-busting firm to discourage workers from organizing. The workers won anyway [and] Trump refused to recognize the union," he said. "[Trump] dragged his feet. He filed an appeal. He did everything except bargain a first contract."

"Sisters and brothers, if you actively block our fundamental right to speak up together for better wages and benefits, you will never, ever, ever get our support," Trumka told the crowd.

Trumka later encouraged those in attendance to stand together and defeat Trump's "misguided, petty and unnecessary politics of division and disunity" by sending a message to Republicans who've allowed Trump to the become the standard-bearer of their party that they need to "change course or face extinction."

In addition to Trumka's blistering critique of Trump, the AFL-CIO had launched direct mail initiatives in Florida, Ohio, Nevada, Pennsylvania and Wisconsin that aim to promote Hillary Clinton as the trusted champion of working-class voters. The union federation endorsed Clinton shortly after she clinched the Democratic presidential nomination in mid-June.