Trump accuses Steve Bannon of 'losing his mind' in response to series of explosive Russia claims

President Donald Trump has slammed former adviser Steve Bannon, claiming the political strategist had "lost his mind," after he was quoted calling a Trump campaign meeting "treasonous".

"Steve Bannon has nothing to do with me or my Presidency," Mr Trump said in a statement. "When he was fired, he not only lost his job, he lost his mind."

He added: "Steve had very little to do with our historic victory, which was delivered by the forgotten men and women of this country ... Steve doesn’t represent my base—he’s only in it for himself."

The comments came in the wake of an explosive report in which Mr Bannon was quoted mocking a June 2016 meeting between key members of the Trump campaign and Russian lawyer Natalia Veselnitskaya. Mr Trump's son, Donald Trump Jr, agreed to the meeting after an intermediary promised "dirt" from Russia on campaign rival Hillary Clinton.

“Even if you thought that this was not treasonous, or unpatriotic, or bad s***, and I happen to think it’s all of that, you should have called the FBI immediately," Mr Bannon said of the meeting, according to journalist Michael Wolff.

The meeting has been of intense interest to Congressional investigators, as well as special counsel Robert Mueller, who is investigating possible collusion between the Trump campaign and Russia.

Mr Trump issued his fiery response in an official White House statement hours after the report first surfaced. He accused Mr Bannon, once thought to be his most trusted adviser, of leaking false information to the media, and downplayed his former White House role.

"Steve was rarely in a one-on-one meeting with me and only pretends to have had influence to fool a few people with no access and no clue, whom he helped write phony books," Mr Trump said.

Mr Bannon was seen as a key architect of the Trump campaign, helping the candidate tap into his populist message and pushing him towards more nationalist ideas. He was also a driving force behind Trump administration policies like the travel ban and the repeal of Obama-era regulations.

Mr Bannon left the White House in August, amid controversy over the President's response to a white supremacist rally in Virginia. Close advisers had long urged Mr Trump to oust his chief strategist, and the President himself was beginning to suspect him of leaking to the press, according to the New York Times.

Nonetheless, Mr Trump complemented Mr Bannon as he left to resume a leadership role at Breitbart News.

"Steve Bannon will be a tough and smart new voice at Breitbart News ... maybe even better than ever before," Mr Trump tweeted at the time. "Fake news needs the competition!"

Mr Bannon went on to work with Alabama Judge Roy Moore on his ill-fated Senate campaign. Mr Moore lost the race after being accused of sexual misconduct with underage women, giving Alabama its first Democratic senator in 25 years.

Mr Trump taunted his former adviser for the loss in his statement, writing: "Now that he is on his own, Steve is learning that winning isn’t as easy as I make it look."

"Steve had very little to do with our historic victory, which was delivered by the forgotten men and women of this country.," he added. "Yet Steve had everything to do with the loss of a Senate seat in Alabama held for more than thirty years by Republicans."