"I have no problem if he comes and testifies. It would be very interesting. I'd like to know what he was unhappy about," Kennedy, a member of the Senate Judiciary Committee, told reporters.

ADVERTISEMENT Reports have emerged over the past 24 hours indicating that Mueller had expressed frustration to Attorney General William Barr about the attorney general's initial handling of the special counsel's report once it was filed in March.

Mueller twice asked Barr to release the special counsel's own summary of his findings from the 448-page report, according to a letter released Wednesday. Barr had initially summarized Mueller's findings in a four-page letter to Congress on March 24.

Kennedy's comments came as Barr testified Wednesday before the Judiciary panel about his handling of Mueller's report on his findings from the nearly two-year probe into Russian interference in the 2016 election and potential obstruction of justice.

Graham has indicated that he has no intention of asking Mueller to testify before his panel, and other Republicans have signaled a desire to move on from the Russia probe.

"I appreciate very much what Mr. Mueller did for the country. I have read most of the report. For me, it is over," Graham said as part of his opening statement at Wednesday's hearing.