Mr Barr said he may send Congress a summary of Mr Mueller's findings as soon as this weekend.
The comprehensive report, still confidential, marks the end of Mueller's probe but sets the stage for big public fights to come. It also discloses, in accordance with federal regulations, that Mueller was not, at any point, overruled by Barr or by Deputy Attorney General Rod Rosenstein in the course of his investigation. The Special Counsel's report must be provided to Congress immediately, and the Attorney General should swiftly prepare a declassified version of the report for the public.
Mr Trump said: "I have a deputy, appoints a man to write a report on me, to make a determination on my presidency".
House Speaker Nancy Pelosi, D-Calif., and Senate Minority Leader Chuck Schumer, D-N.Y., released a joint statement on the report after the early-evening disclosure on the submission. Longtime Trump confidant Roger Stone was charged in January with obstruction, false statements and witness tampering.
MSNBC's Katy Tur dismissed the upcoming results of Robert Mueller's investigation during her Thursday show because, according to her, the special counsel has already found "quite a bit" of incriminating evidence against President Donald Trump.
His prosecutors revealed a sweeping criminal effort by Russians to interfere in the 2016 presidential election and showed that people connected to the Trump campaign were eager to exploit emails stolen from Democrats.
Monsanto found responsible for cancer case by USA court
Pharmaceutical group Bayer had strongly rejected claims that its glyphosate-based Roundup product was carcinogenic. Litzenburg said he and other attorneys have more than 4,000 similar cases awaiting trial in various state courts.
But Friday's reports suggest that any further charges will not come from the special counsel, if they come at all.
Cohen, the president's former lawyer, pleaded guilty in NY to campaign finance violations arising from the hush money payments and in the Mueller probe to lying to Congress about a Moscow real estate deal.
What exactly was Mueller investigating again? .
The source says President Trump was not outside with the staff.
Several House committees in the meantime are conducting aggressive investigations of Trump and people around him.
Mr Trump and other Republicans have repeatedly condemned the probe as a partisan "witch hunt".
On Capitol Hill, Cohen testified publicly last month, accusing Trump of directing him to issue hush-money payments to two women alleging affairs, which Trump has denied, and alleging Trump committed financial fraud.