Former President Donald Trump called Democrats and others who have opposed or investigated him “the enemy from within” in an interview broadcast Sunday, describing them as more dangerous than the United States' top foreign adversaries, including Russia and China.

Trump singled out those he called the “crazy we have inside us, like Adam Schiff,” in particular, referring to the California representative and Democratic candidate for Senate who was the lead prosecutor in the then-President's first impeachment trial Senate was.

During a prepared interview on Fox News' “Sunday Morning Futures,” Trump was asked by host Maria Bartiromo how he would deal with bureaucrats who might try to undermine him in a possible second term.

“I always say we have two enemies,” Trump said, adding: “We have the enemy without, and then we have the enemy within, and the enemy within is, in my opinion, more dangerous than China, Russia and… “all these countries.”

Trump added that a “smart president” can deal with external adversaries “pretty easily,” but “what's harder to deal with are these crazy people that we have inside us, like Adam Schiff.”

“I call him the enemy within,” he added.

As the 2024 presidential election enters its final weeks, the Republican candidate has increasingly described his opponents, including Vice President Kamala Harris, as criminals and described critical statements about him or his policies as illegal – a rhetorical focus of his in previous elections.

Trump's comments on Sunday echoed comments he made Saturday night at a rally in Coachella, California, where he called Schiff a “shady ship” and “the enemy from within.”

“He came up with the Russia hoax. … He’s a sick person,” Trump said.

In response to a request for comment from NBC News on Sunday, Schiff's campaign pointed to a series of tweets the Democratic congressman posted Saturday evening in response to Trump's rally remarks.

“Yet another nonsensical rant about me, full of tired insults, lies about voting booths and more, this time in my home state of California. Seriously, Donald. “Why are you so obsessed with me?” Schiff wrote.

The former president has long had an adversarial relationship with Schiff, dating back to the congressman's work as one of the impeachment managers at Trump's first impeachment trial in 2019. In posts on Truth Social, Trump has often called the congressman “shady” and claimed that he improperly investigated Trump's ties to Russia during the impeachment inquiry.

House Republicans have joined Trump in his anger against Schiff, who is leading the California Senate race against former baseball player Steve Garvey, a Republican.

In 2023, House Republicans censured Schiff in the House, claiming he misrepresented special counsel Robert Mueller's investigation into the Trump campaign's 2016 contacts with Russia. Mueller's report found that the Trump campaign and Russia did not make an explicit coordinated effort to influence the election.

“Look at the danger he has put our country in, possibly with Russia, with the false, fabricated deal he made with Hillary and some bad people … which was used as an excuse for why she lost an election .” “A lot of people thought she should have won,” Trump added on Sunday.

When asked about the upcoming election, Trump sought to allay fears expressed by President Joe Biden earlier this month that there could be another 2020-style chaos.

“No, I don’t think so, not from the side that votes for Trump,” the former president said, adding that the problems surrounding the election were not due to foreign agitators or foreign nations.

“I think the bigger problem is the enemy from within… We have some very bad people, we have some sick people, radical left-wing lunatics,” he said.

Any unrest, Trump said, “should be dealt with very easily by the National Guard if necessary or by the military if it's really necessary, because they can't let that happen.”

The National Guard's response to the Jan. 6 attack on the Capitol was famously delayed for hours, in part because Trump did not ask for it to be deployed on the day of the insurrection.