President Trump claims former Acting FBI Director Andrew McCabe and current Deputy Attorney General Rod Rosenstein were planning an "illegal act", after McCabe alleged in a "60 Minutes" interview that Rosenstein mentioned the 25th Amendment process for removing a sitting president.
In December, CNN reported that after the firing of then-FBI Director James Comey, McCabe took the extraordinary step of opening an obstruction of justice investigation into the President before special counsel Robert Mueller was appointed in May 2017.
Trump said on Twitter that McCabe's "story gets even more deranged".
In the interview, McCabe was asked whether Rosenstein seemed intent on "getting rid of the president of the United States one way or another".
During the 60 Minutes interview yesterday, McCabe said revealed Rosenstein was discussing invoking the Constitution's 25th Amendment, which allows Cabinet members to seek the removal of a president if they conclude that he or she is mentally unfit.
In March 2018, US President Donald Trump called the firing of former Federal Bureau of Investigation deputy director Andrew McCabe earlier that month a "great day for democracy" as he slammed the agency for being corrupt.
McCabe was sacked by then-Attorney General Jeff Sessions previous year over a report that he wasn't forthcoming in his own testimony, although McCabe claims he was sacked because he opened a case against the president.
"Intelligence officials in the briefing responded that that was not consistent with any of the intelligence our government possesses", McCabe said.
He said he also thinks that anyone who was in the room discussing an investigation into Trump should be put under oath and asked "what were they thinking?"
On Sunday Senator Elizabeth Warren, a Massachusetts Democrat who is seeking her party's nomination for president, told reporters that if the people around Mr Trump believe he can not fulfil the obligations of his office, then they have a duty to invoke the 25th Amendment. To spend that time and effort and energy and that we all do in the intelligence community to produce products that will help decision-makers - and the ultimate decision-maker, the President of the United States - make policy decisions.
While McCabe stands firmly on his claim, Deputy Attorney General Rod Rosenstein denies that the talks ever occurred in a serious fashion, only admitting to joking about the issue.
The allegation was referred to the US Attorney's office in Washington for possible prosecution, but no charges have been brought.
"I was taken aback by the offer", McCabe said. "I don't know that we have ever seen in all of history an example of the number, the volume and the significance of the contacts between people in and around the president, his campaign, with our most serious, our existential worldwide enemy: the government of Russian Federation", he told NPR's Morning Edition.
Statements like "I believe Putin" made McCabe so concerned about the President's motivation that he ordered intelligence officers to launch a probe into possible obstruction of justice.