Former White House aide Steve Bannon “lost his mind” after he lost his job at the White House, US President Donald Trump has said.

The president disavowed Mr Bannon after he was quoted in a new book describing a meeting between Mr Trump’s son and a group of Russians as “treasonous”.

The Russians had offered Donald Trump Jr damaging information on Hillary Clinton at the June 2016 meeting.

Mr Bannon’s quote appears in a new book by journalist Michael Wolff.

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

“Steve was a staffer who worked for me after I had already won the nomination by defeating seventeen candidates, often described as the most talented field ever assembled in the Republican party,” he continued.

“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.”