Special counsel Robert Mueller’s team of investigators has expressed interest in speaking with Donald Trump as its investigation into potential coordination between Russia and the president’s election campaign looks set to reach right into the Oval Office, it emerged on Monday.

No details are set at this stage, including a date for any possible interview, the scope of questions or even whether an interview will take place, according to a person familiar with the matter, who spoke to the Associated Press on condition of anonymity.

But the source expressed the view that it was not surprising that Mueller’s team would want to interview Trump as part of the investigation that got under way last year and has been working its way closer and closer to the ultimate seat of power.

Profile Who is Robert Mueller? Show Hide Background Robert S Mueller III, 74, is a former FBI director who was appointed by George W Bush and held over by Barack Obama beyond his 10-year term. The term extension required special congressional action which the Senate approved 100-0. Previously, Mueller held two different US attorney posts and was an assistant attorney general in the George HW Bush administration.

Special counsel Mueller was appointed special counsel in May 2017, eight days after Trump fired FBI director James Comey. A special counsel is a prosecutor appointed in extraordinary circumstances or in cases of conflicts of interest within the justice department. In this case, there was a need for someone to investigate the Russian matter who was not appointed by or beholden to Trump. Mueller’s team of 17 lawyers operates independently of, but (ideally) in cooperation with, Congress, which has three committees conducting investigations in parallel to Mueller. Mueller is expected to submit a report to Congress and may bring criminal charges separately. Mueller has a sizeable budget and an open-ended term. He is specifically authorized to investigate “any links and/or coordination between the Russian government and individuals associated with the campaign of President Donald Trump” plus any matters that “may arise directly from the investigation”. He has the power to prosecute federal crimes. Can he be replaced? In theory, William Barr, the new attorney general, could fire Mueller. Barr, who once criticised Mueller's case as “fatally misconceived”, was asked during his confirmation hearing if he would fire the special counsel without good cause and replied: "I would not carry out that instruction." Although, if Trump wanted to fire Mueller, and Barr was unwilling, Trump could replace Barr. Trump's view Trump has said Mueller “is very, very good friends with [James] Comey, which is very bothersome” but also said “Robert Mueller is an honorable man.” Photograph: Saul Loeb/AFP

Trump has insisted there was “no collusion” between his campaign team and anyone connected with the Russian government who might have been involved in any effort to interfere with the 2016 election and sway it in his favor. He repeated this assertion 16 times in a 30-minute impromptu interview with the New York Times at his golf club in Florida shortly after Christmas.

Trump’s former campaign manager Paul Manafort is suing the Department of Justice in an attempt to foil the inquiry, which late last year indicted him on money-laundering charges.

Mueller’s team briefly interviewed Trump’s son-in-law and senior adviser Jared Kushner in November, chiefly in relation to Trump’s fired national security adviser Michael Flynn. In a crucial step for the Russia investigation, it emerged in December that Flynn is cooperating with the investigators after admitting lying to the FBI shortly after the presidential inauguration about conversations he had held with the then Russian ambassador, Sergey Kislyak, concerning US sanctions on Russia and other matters.

Trump-Russia investigation: the key questions answered Read more

At the weekend, former White House chief strategist Steve Bannon apologized for accusing Trump’s eldest son, Donald Jr, of treasonous and unpatriotic conduct in meeting with Russians at Trump Tower during the election. This was just one of many explosive criticisms of Trump, Bannon’s former boss, his staff and family in media commentator Michael Wolff’s instant-blockbuster book Fire and Fury about the the Trump administration, which was first revealed by the Guardian.

On Monday a spokesman for Mueller declined to comment, as did Trump lawyer John Dowd.

A White House spokesman pointed to a statement from White House lawyer Ty Cobb saying the White House does not publicly discuss its conversations with Mueller.