Democratic presidential candidate Kamala Harris has slammed Donald Trump over his comments about "the enemy within" the United States and his threat to deploy the military domestically.
In a rare move at her own campaign rally in the political swing state Pennsylvania, the US vice president showed a clip of Trump, the former president, telling his supporters "those people are more dangerous - the enemy from within - than Russia".
Harris, 59, has recently pressed Trump to release his health records, as she has, and knocked him for going on meandering tangents and focusing on fictional characters such as Hannibal Lecter.
"A second Trump term would be a huge risk for America, and dangerous. Donald Trump is increasingly unstable and unhinged," Harris told the crowd after playing the clip.
She said Trump poses a danger because he believes those who do not agree with him are the enemy.
Trump in recent rally speeches has hinted about facing "an enemy from within", more dangerous than a foreign adversary. His campaign did not immediately return a request for comment.
In an interview on Fox News Trump was asked if he was expecting "chaos" on election day, and he appeared to suggest the military could be deployed against citizens.
"I think the bigger problem is the enemy from within," Trump said. "We have some very bad people. We have some sick people, radical left lunatics.
"It should be very easily handled by, if necessary, by National Guard, or if really necessary, by the military, because they can't let that happen."
Harris's trip to Pennsylvania on Monday is her 10th to the battleground state since becoming the Democratic candidate in July.
The state's 19 electoral college votes will be pivotal to the election outcome.
She kicked off her trip to Erie with a stop at a Black-owned coffee shop for a sit-down discussion with Black men. Her campaign is concerned about slipping support from Black voters.
Harris unveiled new policy proposals aimed at Black men on Monday that include forgivable small business loans and access to a new legal recreational marijuana industry.
The Harris campaign and Democrats - including former president Barack Obama - have expressed deep concern about whether Black men will turn out in numbers seen in past elections and whether they will support Harris or Trump.
More than a quarter of young Black men say they would support Trump in the election race, according to a September poll by the NAACP, the nation's largest civil rights organisation.
US President Joe Biden got about 80 per cent of the Black male vote in 2020.
