The move by Special Counsel Robert S. Mueller III to investigate Trump’s own conduct marks a major turning point in the nearly year-old FBI investigation, which until recently focused on Russian meddling during the presidential campaign and on whether there was any coordination between the Trump campaign and the Kremlin. Investigators have also been looking for any evidence of possible financial crimes among Trump associates, officials said.

Trump had received private assurances from former FBI Director James B. Comey starting in January that he was not personally under investigation. Officials say that changed shortly after Comey’s firing.

Five people briefed on the requests, who spoke on condition of anonymity because they were not authorized to discuss the matter publicly, said Daniel Coats, the current director of national intelligence, Adm. Mike Rogers, head of the National Security Agency, and Rogers’ recently departed deputy, Richard Ledgett, agreed to be interviewed by Mueller’s investigators as early as this week. The investigation has been cloaked in secrecy and it’s unclear how many others have been questioned by the FBI.