FILE PHOTO: Reince Priebus boards Air Force One to travel with U.S. President Donald Trump to Ronkonkoma, New York from Joint Base Andrews, Maryland, U.S., July 28, 2017. REUTERS/Carlos Barria/File Photo

(Reuters) - President Donald Trump’s former White House Chief of Staff Reince Priebus was interviewed on Friday by the special counsel investigating whether the Trump campaign colluded with Russia during the 2016 U.S. election.

“Mr. Priebus was voluntarily interviewed by Special Counsel Mueller’s team today,” said his lawyer, William Burck. “He was happy to answer all of their questions.”

Special Counsel Robert Mueller’s investigators are interviewing a number of White House and other officials as part of the inquiry into any ties between Trump’s presidential campaign and Russia.

Mueller’s inquiry includes whether Trump might have obstructed justice by trying to persuade then-FBI Director James Comey to drop an investigation of Michael Flynn, the president’s first national security adviser.

Flynn resigned in February after disclosures that he had discussed U.S. sanctions on Russia with the Russian ambassador to the United States before Trump took office and misled Vice President Mike Pence about the conversations.

Priebus, who was Republican National Committee chairman during the campaign, became White House chief of staff upon Trump’s taking office in January. He resigned in July after major pieces of legislation on Trump’s agenda failed to pass Congress.