Senate Majority Leader Mitch McConnell on Friday suggested he would not allow a floor vote on legislation to protect the special counsel Robert Mueller.

"It's not necessary. The Mueller investigation is not under threat," McConnell told reporters.

This comes two days after the dramatic ousting of Attorney General Jeff Sessions, who's been replaced for the time being by acting Attorney General Matthew Whitaker.

Whitaker has publicly criticized the Mueller investigation, prompting concerns he would move to shut it down.

Senate Majority Leader Mitch McConnell on Friday suggested he would not allow a floor vote on legislation to protect the special counsel Robert Mueller, who is investigating Russian election interference and alleged collusion by the Trump campaign.

"It's not necessary. The Mueller investigation is not under threat," McConnell told reporters.

This comes two days after the dramatic ousting of Attorney General Jeff Sessions, who's been replaced for the time being by acting Attorney General Matthew Whitaker, Sessions' former chief of staff. Sessions said he resigned at the request of the president, and his departure was made public the day after the 2018 midterm elections.

Read more: Jeff Sessions resigns as attorney general at Trump's request

Whitaker has publicly criticized the Mueller investigation, prompting concerns he would move to shut it down. In this context, Republican Sen. Jeff Flake on Thursday said he and Democratic Sen. Chris Coons planned to call for a floor vote on legislation to protect Mueller.

Trump on Friday lambasted Flake via Twitter over these efforts.

The president tweeted, "Jeff Flake(y) doesn’t want to protect the Non-Senate confirmed Special Counsel, he wants to protect his future after being unelectable in Arizona for the 'crime' of doing a terrible job! A weak and ineffective guy!"

There have been broad calls for Whitaker to recuse himself from the probe. McConnell on Friday said he didn't "have any advice to give the administration on that."

McConnell added that he expects "we'll get a new nominee quickly for the job."

Some legal experts, including the husband of White House counsel Kellyanne Conway, have argued Whitaker's elevation is unconstitutional given he was not confirmed by the Senate. Other Senate-confirmed Department of Justice officials were available for the position, but Trump still went forward and tapped Whitaker.

Beyond Congress, the US public has also expressed deep concern about the chaos within the Department of Justice.

On Thursday night, people in cities across the US participated in the #ProtectMueller march in support of the special counsel, declaring "Trump is not above the law."