Former FBI deputy director Andrew McCabe has been fired in what he considers US President Donald Trump’s latest attempt to undermine investigations into Russian interference in the 2016 US election.

Attorney General Jeff Sessions said he decided to fire Mr McCabe “effective immediately” based on a Justice Department internal watchdog recommendation.

The allegations suggested the FBI’s former No. 2 misled investigators about authorising discussions with a news reporter and the bureau’s handling of the Hilary Clinton email investigation.

“Based on the report of the Inspector General, the findings of the FBI Office of Professional Responsibility, and the recommendation of the Department’s senior career official, I have terminated the employment of Andrew McCabe effective immediately,” Mr Sessions said in a statement.

In response, Mr McCabe said he was being targeted because he corroborated ousted former FBI director James Comey’s claims that Mr Trump tried to pressure him into censoring the Russia probe.

“I am being singled out and treated this way because of the role I played, the actions I took, and the vents I witnesses in the aftermath of the firing of James Comey,” he said in a statement.

In a tweet, Donald Trump said the firing of Mr McCabe was a “great day”.

Andrew McCabe FIRED, a great day for the hard working men and women of the FBI – A great day for Democracy. Sanctimonious James Comey was his boss and made McCabe look like a choirboy. He knew all about the lies and corruption going on at the highest levels of the FBI!

— Donald J. Trump (@realDonaldTrump) March 17, 2018

The White House on Thursday (AEDT) said Mr McCabe’s actions atop the FBI presented “some cause for concern”.

“We do think that it is well documented that he has had some very troubling behaviour and [is] by most accounts a bad actor,” White House spokeswoman Sarah Sanders said.

Mr McCabe had stepped down from his position as FBI deputy director in January but remained on leave pending retirement after a 21-year career.

The firing also jeopardises the 50-year-old FBI veteran’s eligibility for a government pension.

“It’s incredibly unfair to my reputation after a 21-year career,” Mr McCabe said.

“The real damage is being done to the FBI, law enforcement and the special counsel.”

Mr McCabe told ABC News in the US he firmly believed what had happened to him was “just a piece of an ongoing assault” on the FBI and special counsel Robert Mueller, who is currently investigating Russia’s purported efforts to help Mr Trump win the 2016 election and alleged collusion between Trump associates and Russian operatives.

The FBI veteran’s dismissal is the latest casualty in an ever-growing list of cabinet members, senior government officials and civil service appointments, with 25 White House officials having either resigned or been fired since Mr Trump took office in January, 2017.

-with AAP