President-elect Donald Trump took aim at outgoing CIA Director John Brennan late Sunday suggesting that he was behind the unverified dossier of scandalous opposition material that BuzzFeed published last week.

Trump's comments came in response to Brennan saying on "Fox News Sunday" over the weekend that he doesn't think Trump understands or has an "appreciation" for the effect that his words have on the U.S. intelligence community and U.S. national security.

Brennan was responding to weeks of comments from Trump, who since being elected president, has been openly critical of the U.S. intelligence community after they declared late last year that Russia likely attempted to manipulate the presidential election to undermine American democracy.

So Trump responded to Brennan in the best way he knows how: via Twitter.

".@FoxNews 'Outgoing CIA Chief, John Brennan, blasts Pres-Elect Trump on Russia threat. Does not fully understand.' Oh really, couldn't do much worse - just look at Syria (red line), Crimea, Ukraine and the build-up of Russian nukes. Not good! Was this the leaker of Fake News?" Trump tweeted Sunday.

The unverified, 35-page dossier published only by BuzzFeed last week is the "fake news" that Trump was referring to in his tweet. CNN was first to report on the existence of the dossier, but chose not to publish it because of the very questionable "intelligence" it contains.

Despite Trump's consistent claims that the dossier was the result of an intelligence leak, Director of National Intelligence James Clapper took the unusual step last week of publicly saying that he didn't believe it was the result of a leak in the intelligence community.

"I emphasized that this document is not a U.S. Intelligence Community product and that I do not believe the leaks came from within the IC," Clapper said last week, referring to a phone conversation he had with Trump, according to Talking Points Memo.

Still, Trump has been very outspoken in his criticism of the dossier and what he believes to be the intelligence community's role it in being leaked to the media. Last week, Trump tweeted that the leak was characteristic of something from Nazi Germany:

However, that comment was quickly rebuked. In fact, Brennen, in his interview with "Fox News Sunday," also denounced Trump for that comment.

"What I do find outrageous is equating the intelligence community with Nazi Germany. I do take great umbrage at that, and there is no basis for Mr. Trump to point fingers at the intelligence community for leaking information that was already available publicly," Brennan said.