Rudy Giuliani, an ex-lawyer of former U.S. President Donald Trump, has been interviewed as part of a probe by Special Counsel Jack Smith into interference in the 2020 presidential election, CNN reported on Tuesday, citing sources.

Smith is looking into Trump's efforts to overturn the results of the 2020 election that he lost, including a plot to submit phony slates of electors to block Congress from certifying Democrat Joe Biden's victory.

The investigation - in which former Vice President Mike Pence and others who served in top roles in Trump's administration have been subpoenaed - is ongoing.

CNN reported that the meeting involving Giuliani, his attorney Robert Costello and investigators happened in recent weeks.

Neither Smith's office nor Costello immediately responded to separate emailed requests for comment from Reuters.

(Reporting by Costas Pitas; Editing by Leslie Adler)