WASHINGTON (AFP) - The US deputy attorney-general discussed how many Cabinet members would support removing US President Donald Trump from office in 2017, the FBI's former acting director said in an interview airing on Sunday (Feb 17).

Mr Andrew McCabe said invoking the 25th Amendment of the US Constitution was raised by Deputy Attorney-General Rod Rosenstein after Mr Trump fired FBI director James Comey on May 9, 2017.

"Rod raised the issue and discussed it with me in the context of thinking about how many other Cabinet officials might support such an effort," Mr McCabe told CBS's 60 Minutes news show.

A clip of that part of the interview was run early on Sunday on CBS's Face the Nation show, the first time Mr McCabe's actual comments on the explosive subject have been aired.

Mr Rosenstein has dismissed reports that he discussed removing Mr Trump from office - and even pondered wearing a wire to secretly record his conversations with the President - as a "joke", if indeed he made the comments.

In the interview, Mr McCabe was asked whether Mr Rosenstein seemed intent on "getting rid of the President of the United States one way or another".

"I can't confirm that," he said. "But what I can say is the deputy attorney-general was definitely very concerned about the president, about his capacity and about his intent at that point in time."

The President abruptly fired Mr Comey amid tensions over the FBI's investigation into possible links between Mr Trump's 2016 campaign and a covert Russian effort to sway the US election in his favour.

Mr Comey has said that Mr Trump had been pressuring him to publicly declare that he was not a subject of the investigation.

The firing set off alarm bells at the FBI, and Mr McCabe told CBS he scrambled to ensure that the Russia probe was on "absolutely solid ground" so it could not easily be shelved.

He told CBS he did not remember how the 25th Amendment came up in the discussion with Mr Rosenstein.

"It was just another kind of topic that he jumped to in the midst of a wide-ranging conversation," he said.

The 25th Amendment sets out a process for the replacement of the President in the event of death, removal, resignation or incapacitation.

Mr McCabe himself was fired in March 2018 for "lack of candour" in an internal investigation into the FBI's handling of a 2016 probe into Trump's Democratic rival Hillary Clinton.