One of the US government's most senior lawyers who oversaw the investigation into links between the Trump presidential campaign and Russia is to step down, a justice department official has said.

Deputy attorney general Rod Rosenstein, who took on the investigation after his boss Jeff Sessions had to disqualify himself, is expected to leave his position in the middle of next month.

It comes a day after Andrew McCabe, the former acting director of the FBI, said he and Mr Rosenstein discussed invoking an amendment to the US constitution that would have allowed them to remove Donald Trump as president.

It prompted Mr Trump to say it looked like the pair were "planning a very illegal act".

Reuters said the justice department official it spoke to claimed Mr Rosenstein's departure was not related to allegations he considered wearing a wire in meetings with Mr Trump and using the 25th amendment of the US Constitution to remove the president from office.


Image: Former acting FBI director Andrew McCabe accused Mr Rosenstein of offering to wear a wire to record Mr Trump

A registered Republican, Mr Rosenstein appointed special counsel Robert Mueller to lead an investigation into Mr Trump's campaign because Mr Sessions, the former attorney general and a Trump supporter during the 2016 campaign, felt he was not sufficiently independent.

Mr Mueller's appointment came after Mr Trump's firing of James Comey, the former head of the FBI.

Mr McCabe, in a CBS interview broadcast on Sunday night, said he had met Mr Rosenstein after Mr Comey was fired.

During the meeting according to Mr McCabe, Mr Rosenstein raised the idea of wearing a wire while speaking with Mr Trump, and exploring whether cabinet members could invoke the 25th amendment to the constitution, which allows the vice president and a "majority" of cabinet members to declare a president incapable.

Image: Mr Rosenstein appointed special counsel Robert Mueller to lead the Trump-Russia inquiry

At around the same time, Mr McCabe opened an obstruction of justice case, looking at whether Mr Trump had interfered in the judicial process.

Mr McCabe was later fired after being accused of misleading investigators during an investigation into a press leak, something he denied.

Mr Rosenstein said Mr McCabe's account was "inaccurate and factually incorrect" - as did a justice department spokeswoman.

The deputy attorney general stopped overseeing the inquiry by Robert Mueller on 7 November when Mr Trump named Matt Whittaker acting attorney general.

He has since appointed a new attorney general, William Barr, who is expected to take up the role in the coming weeks.

Analysts say Mr Rosenstein had been expected to depart shortly after Mr Barr assumed office. Mr Barr's appointment was approved by the US Senate last week.

Image: Analysts say Mr Rosenstein was expected to leave after the appointment of new attorney general William Barr

Number twos in the justice department are not normally in the spotlight to the extent that Mr Rosenstein has been.

But his decision to appoint Mr Mueller as special counsel and Mr Trump's hostility to the investigation has put him under scrutiny.

Mr Trump frequently comments angrily about the Mueller inquiry, the Federal Bureau of Investigation and the justice department, which oversees them both.

The president denies any collusion and often calls Mr Mueller's investigation a "witch hunt".

So far the Mueller inquiry has netted 34 individuals and three companies who have pleaded guilty, been indicted or been otherwise caught up in the inquiry.