"I think the bigger problem is the enemy from within, not even the people that have come in and destroyed our country," Trump told Fox News show "Sunday Morning Futures," referring to American citizens as opposed to migrants he criticizes for flooding into the country.

"We have some very bad people, we have some sick people, radical left lunatics. And I think they're the -- and it should be very easily handled by, if necessary, by National Guard or, if really necessary, by the military," Trump said. "Because they can't let that happen."

The Republican former president was responding to a question about what he expects will transpire on Election Day, after President Joe Biden said last week that while he believed the vote would be free and fair, he did not know "whether it will be peaceful."

Trump claimed in his remarks that fellow Americans are "more dangerous than China, Russia and all these countries."

The campaign of Vice President Kamala Harris, Trump's Democratic rival in the presidential race, swiftly pushed back on the Republican's extraordinary remarks.

"I know people have grown numb to Trump over the past decade, but this should be shocking" to Americans, said Ian Sams, a Harris campaign spokesman.

"Donald Trump is suggesting that his fellow Americans are worse 'enemies' than foreign adversaries, and he is saying he would use the military against them," Sams said.

"Taken with the Supreme Court's decision to give presidents immunity (for their official actions as commander in chief), and Trump's vow to be a 'dictator on day one' willing to allow the 'termination' of the Constitution... Scary stuff," he added on social media platform X.

Trump has alleged widespread fraud after his 2020 defeat to Biden and continues to repeat the baseless and widely debunked claim that he did not lose.

Pro-Trump rioters, riled up by his false claims, ransacked the US Capitol in Washington on January 6, 2021 in a vain attempt to halt the election's certification.

Following two failed assassination attempts on Trump in as many months, the Republican reportedly has requested to use a military aircraft in the final weeks of the campaign.