Washington: Robert Mueller III, the special counsel, has asked the White House for documents about some of President Donald Trump's most scrutinised actions since taking office, including the firing of his national security adviser and FBI director, according to White House officials.

Mueller is also interested in an Oval Office meeting Trump had with Russian officials in which he said the dismissal of the FBI director had relieved "great pressure" on him.

Special counsel Robert Mueller is investigating "the Russia thing". Credit:AP

The document requests provide the most details to date about the breadth of Mueller's investigation, and show that several aspects of his inquiry are focused squarely on Trump's behaviour in the White House.

In recent weeks, Mueller's office sent a document to the White House that detailed 13 different areas that investigators want more information about. Since then, administration lawyers have been scouring White House emails and asking officials whether they have other documents or notes that may pertain to Mueller's requests.