Washington: It appears Russia probe Special Counsel Robert Mueller is willing to reduce the number of questions his investigators would pose to US President Donald Trump in an interview, in an effort to convince Trump's lawyers about a presidential sit-down, according to two people briefed on the negotiations.

The latest proposal by the special counsel comes after a long stand-off and as Trump has stepped up his attacks on his investigation and on Mueller personally.

Mueller has been seeking to question the President as part of his probe into Russia interference in the 2016 campaign, which is also examining whether Trump has sought to block that probe.

In a letter sent on Monday, Mueller's team suggested that investigators would reduce the number of questions about potential obstruction of justice they would ask in person and instead seek some answers in written form, according to one person.