Read: Attorney General William Barr's Letter Announcing End of Robert Mueller's Investigation

After a long wait from the American public, Attorney General William Barr announced via a letter to members of the Senate and House Judiciary Committees on Friday that special counsel Robert Mueller had concluded his investigation into Russian interference in the 2016 election.

As it stands, the public still has not seen the report. But in the letter, Barr wrote: "I am reviewing the report and anticipate that I may be in a position to advise you of the Special Counsel's principal conclusions as soon as this weekend."

The letter read:

"Dear Chairman Graham, Chairman Nadler, Ranking Member Feinstein, and Ranking Member Collins:

I write to notify you pursuant to 28 C.F.R. 600.9(a)(3) that Special Counsel Robert S. Mueller III has concluded his investigation of Russian interference in the 2016 election and related matters. In addition to this notification, the Special Counsel regulations require that I provide you with 'a description and explanation of instances (if any) in which the Attorney General' or acting Attorney General 'concluded that a proposed action by a Special Counsel was so inappropriate or unwarranted under established Departmental practices that it should not be pursued.' 28 C.F.R. 600.9(a)(3). There were no such instances during the Special Counsel's investigation.

The Special Counsel has submitted to me today a 'confidential report explaining the prosecution or declination decisions' he has reached, as required by 28 C.F.R. 600.8(c). I am reviewing the report and anticipate that I may be in a position to advise you of the Special Counsel's principal conclusions as soon as this weekend.

Separately, I intend to consult with Deputy Attorney General Rosenstein and Special Counsel Mueller to determine what other information from the report can be released to Congress and the public consistent with the law, including the Special Counsel regulations, and the Department's long-standing practices and policies. I remain committed to as much transparency as possible, and I will keep you informed as to the status of my review.

Finally, the Special Counsel regulations provide that 'the Attorney General may determine that public release of' this notification 'would be in the public interest.' 28 C.F.R. 600.9(c) I have so determined, and I will disclose this letter to the public after delivering it to you.

Sincerely,

William P. Barr

Attorney General"

At present, it is unclear how much information from Mueller's report will be released to Congress and to the public. Democratic lawmakers can be expected to push to have as much information as possible made public.

"This report should be made public immediately," tweeted Democratic New Jersey Senator Cory Booker nearly immediately after news broke that Mueller had submitted his report.

The White House said on Friday evening it had not yet reviewed the report.

"The next steps are up to Attorney General Barr, and we look forward to the process taking its course," White House Press Secretary Sarah Sanders said in a tweet. "The White House has not received or been briefed on the Special Counsel's report."