Senate Majority Leader Mitch McConnell (R-Ky.) is signaling that he believes special counsel Robert Mueller needs to end his probe into the 2016 presidential election, noting the investigation has gone on "forever."

"What I think about the Mueller investigation is, they ought to wrap it up. It's gone on seemingly forever and I don't know how much more they think they can find out," the Kentucky Republican told the Washington Examiner, when asked if he still had confidence in the investigation.

McConnell added that if the Justice Department's inspector general - who released a report on the FBI's handling of the Hillary Clinton email investigation on Thursday - had finished, "why can't the Mueller investigation finally wrap up?"

McConnell has been publicly supportive of Mueller's investigation into Russian interference in the 2016 election, as well as into potential collusion between the Trump campaign and Moscow.

But he signaled late last month that he would like for the investigation to come to an end soon.

"I think it would be great if we got to a conclusion and got to a conclusion some time soon," McConnell told Fox News at the time.

Trump's allies in the House have been launching attacks on Mueller, as well as top Justice Department officials, for months.

House Majority Leader Kevin McCarthy (R-Calif.) told Fox News on Friday that the Mueller probe "has got to stop," and House Speaker Paul Ryan (R-Wis.) said last month that Mueller should be free to do his job but that he "would like to see it get wrapped up."

Senate Republicans have largely stayed away from trying to put a timeline on the investigation or supporting Trump's belief that Mueller's probe is a "witch hunt."

But McConnell's comments, as well as recent remarks from other top Senate GOP lawmakers, could signal their patience is running thin as Mueller's probe has stretched past the one-year mark and close to the November midterm elections.

"I think Director Mueller would be well advised to wrap up his investigation. Most of the, virtually all of the charging he's done, are for people lying in the investigation or for non-campaign conduct," Sen. John Cornyn (Texas), the No. 2 Senate Republican, told reporters this week.

He added that unless Mueller "wants to be the main focal point of the midterm election, which again is not something the Department of Justice or FBI should be doing, then I think he needs to wrap it up."

GOP Sen. John Thune (S.D.), the No. 3 Senate Republican, told Fox News last month that he thought it was "time for them to begin to start winding this down."

-Updated at 11:19 a.m.