President Trump on Friday tweeted an unverified claim that the FBI placed a mole in his campaign team and suggested that the agency is trying to "frame" him for a crime he didn't commit.

Trump tweeted "Really bad stuff!" while quoting Fox Business Network anchor David Asman in saying the Department of Justice is "out to frame Donald Trump for crimes he didn't commit."

"'Apparently the DOJ put a Spy in the Trump Campaign. This has never been done before and by any means necessary, they are out to frame Donald Trump for crimes he didn't commit.' David Asman @LouDobbs @GreggJarrett Really bad stuff!" he wrote.

Asman appeared to be referring to a National Review article last week that wondered if the FBI had a spy on the Trump campaign.

Earlier this week, Trump lawyer Rudy Giuliani also suggested the FBI may have placed a spy in Trump's presidential campaign.

The New York Times reported last week that a top-secret FBI informant had met with two former Trump campaign advisers, George Papadopoulos and Carter Page, but that story did not say that the Obama administration had planted a spy within the Trump campaign.

The Washington Post reported Thursday that the FBI has reportedly been working in recent weeks to soften the blow if the identity of a top-secret informant who fed information to investigators early on in the Russia probe is revealed.

The moves come as allies of the president are focusing on the alleged informant's role in special counsel Robert Mueller's investigation into possible collusion between the Trump campaign and Russia.

Trump has ramped up his attacks on Mueller's probe in recent weeks, calling the investigation a yearlong "witch hunt" in a tweet Thursday.

Mueller's probe, which reached its anniversary on Thursday, has ensnared several former members of the Trump campaign with criminal charges, including Trump's former campaign chairman Paul Manafort, who faces accusations of bank and tax fraud.