Hillary Clinton says rival Donald Trump is spreading hateful messages online by retweeting white supremacists and anti-Semitic tweets and images to his millions of Twitter followers.
Clinton delivered a speech Thursday in Reno, Nevada, highlighting Trump's support within the "alt-right" movement.
"Alt-right" is short for "alternative right," to distinguish the movement from mainstream conservatism. It's often associated with efforts on the far right to preserve "white identity," oppose multiculturalism and defend "Western values."
"What he's doing is more sinister. He's giving a dog whistle to his supporters," she said. "He says he wants to make America great again, but his message seems to be make America hate again"
Trump has been criticized for failing to immediately denounce the support that he's garnered from white nationalists and supremacist, including former Ku Klux Klan Grand Wizard David Duke.
The Democratic presidential candidate cited a series of hateful remarks posted by Trump's account, including an image of Clinton's face next to a Star of David on a background of dollar bills.
"From the start, Donald Trump has built his campaign on prejudice and paranoia." she said. "There's been a steady stream of bigotry from him."
She also accused the Republican nominee of "pushing discredited conspiracy theories with racist undertones" including suggesting that GOP primary candidate Ted Cruz's father was involved in the Kennedy assassination.
"A man with a long history of racial discrimination who traffics in dark conspiracy theories should never run our government of command our military," she added.
Trump took to social media following Clinton's speech, saying she was "pandering" and called her "fear-mongering."
At a rally in New Hampshire earlier Thursday, Trump lashed out at his opponent, rebuking her claims that he's a racist.
"She lies, she smears, she paints decent Americans as racists," said Trump, who then defended some of the core — and to some people, divisive — ideas of his candidacy.
The Republican nominee's campaign says it has never used the term "alt-right" and disavows "any groups or individuals associated with a message of hate." The campaign suggested her attack was meant to distract from questions swirling around donations to The Clinton Foundation and her use of her private email servers.
"It's the oldest play in the Democratic playbook: say 'You're racist, you're racist, you're racist.' It's a tired, disgusting argument. It's the last refuge of the discredited Democratic politician."
Trump's campaign also responded with a strongly worded statement from a prominent black supporter, Pastor Mark Burns, who says Clinton and her campaign "went to a disgusting new low" with the video tying the Trump Campaign to "horrific racial images."
He called on Clinton to disavow the video.
Trump has scheduled a fundraiser Friday night on the south shore of Lake Tahoe.
Clinton also pushed back on accusations from Trump and others saying she was suffering from poor health.
"His latest paranoid fever dream is about my health. All I can say is, Donald, dream on."
Trump and his allies have said that unspecified maladies leave Clinton unfit to assume the presidency.