Former FBI Director James Comey testifies before a Senate Intelligence Committee hearing on Russia's alleged interference in the 2016 U.S. presidential election on Capitol Hill in Washington, June 8, 2017.

James Comey, the former F.B.I. director fired by President Donald Trump last year, has been interviewed by special counsel Robert Mueller as part of his investigation into ties between the Trump campaign and Russia during the 2016 presidential election.

The New York Times first reported the interview on Tuesday.

The interview, which lasted for several hours, focused heavily on a series of memos Comey wrote after each interaction with Trump. NBC News reported that the interview occurred in late 2017.

In his testimony to the Senate Intelligence Committee in June 2017, Comey said he had turned all his memos over to the special counsel. In the hearing, he also acknowledged leaking one of the memos to the press — in the explicit hope of sparking a special counsel investigation.

Comey was fired by Trump in May 2017, for reasons that were heavily disputed at the time. The Trump administration first claimed that Comey was fired over his handling of the investigation into Hillary Clinton's use of a private email server for government communications.

But soon after, Trump told NBC's Lester Holt that he decided to fire Comey because "this Russia thing with Trump and Russia is a made up story."

The Times also reported that Attorney General Jeff Sessions was questioned by Mueller's investigators last week. Sessions had recused himself from any campaign-related matters in March 2017 after failing to disclose multiple meetings with Russian ambassador, Sergey Kislyak, during the campaign.