Barr has released a four-page letter detailing the principal conclusions of the highly-anticipated report, but has come under pressure from Democrats to release the full document.
The new letter to Congress also says that the DOJ is currently in the process of making redactions to Mueller's report before its release.
The letter says that Justice Department officials are redacting grand jury material, information legally blocked from public release, information that could compromise intelligence sources and methods, and any "information that would unduly infringe on the personal privacy and reputational interests of peripheral third parties.”
Barr said in the letter he is available to testify to congress on May 1 and 2.
The special counsel spent 22 months investigating Russian interference during the 2016 presidential campaign, including whether any Americans knowingly assisted with the Russians’ efforts.
According to Barr, 19 special counsel prosecutors and 40 FBI agents issued more than 2,800 subpoenas, executed nearly 500 search warrants and interviewed approximately 500 witnesses. The results of which amounted to 37 indictments and six guilty pleas.
Democrats in Washington have called for the Mueller report to be released in full, but the attorney general has made clear that certain sensitive grand jury information and other redactions may prevent him from being completely transparent
“Everyone will soon be able to read it on their own,” Barr said in the new letter.
He said in the letter that he would be available to testify on May 1 and 2.
Earlier this week, House Judiciary Committee Chairman Jerry Nadler, D-N.Y. said after discussing the report with Barr on Wednesday that the attorney general wouldn't commit to releasing the full "un-redacted" report, but agreed to testify before his panel "reasonably soon."
The chairman of the Senate Judiciary Committee, Sen. Lindsey Graham, R-S.C. -- who also discussed the report with Barr on Wednesday -- said he expects the attorney general to release “everything that doesn't compromise national security or violate the law,” referring to grand jury information.