WASHINGTON — Special Counsel Robert Mueller on Friday handed in a confidential report on his investigation into Russia's role in the 2016 presidential election and any potential wrongdoing by US President Donald Trump, setting off a clamor from lawmakers in both parties for the document's quick release.

Marking the end of his nearly two-year investigation that ensnared former Trump aides and Russian intelligence officers and cast a cloud over the Republican businessman's presidency, Mueller submitted the report to Attorney General William Barr, the Justice Department said.

Mueller did not recommend any further indictments, a senior Justice Department official said, in a sign that there might be no more criminal charges against Trump associates arising from the investigation. Throughout his investigation, Mueller has brought charges against 34 people and three companies.

The big question now is whether the report contains allegations of wrongdoing by Trump himself or exonerates him. Mueller, a former FBI director, had been examining since May 2017 whether Trump's campaign conspired with Moscow to try to influence the election and whether the Republican president later unlawfully tried to obstruct his investigation.

Trump has denied collusion and obstruction. Russia has denied election interference. Trump has sought to discredit the investigation, calling it a "witch hunt" and accusing Mueller of conflicts of interest. But he said on Wednesday he does not mind if the public is allowed to see the report. — Reuters

The report was not immediately made public. Barr, the top US law enforcement officer and a Trump appointee, will have to decide how much of it to disclose. Barr told lawmakers in a letter he may be able to provide the "principal conclusions" of Mueller's findings to Congress as soon as this weekend and added that he was "committed to as much transparency as possible."

Under regulations governing special counsel investigations, the attorney general must share an outline of Mueller's report with Democratic and Republican leaders of the judiciary committees in Congress but it is largely up to him what to make public.

Key Trump aides, including his former campaign chairman Paul Manafort, national security adviser Michael Flynn and personal lawyer Michael Cohen, have already either been convicted or pleaded guilty to charges brought by Mueller. None of those charges, however, directly related to the question of collusion between the campaign and Moscow. The Justice Department has a policy that sitting presidents cannot face criminal charges.

Lawmakers from both parties called for prompt release of the report. House of Representatives Speaker Nancy Pelosi and Senate Democratic leader Chuck Schumer — the two top Democrats in Congress — said it was "imperative" the full report be made public, that Barr not give Trump and his team a "sneak preview" of the findings and that the White House not be allowed to interfere in decisions about what parts are made public.

They said the investigation focused on questions that "go to the integrity of our democracy itself: whether foreign powers corruptly interfered in our elections, and whether unlawful means were used to hinder that investigation."

Senate Majority Leader Mitch McConnell, the top Republican in Congress, said, "The attorney general has said he intends to provide as much information as possible. As I have said previously, I sincerely hope he will do so as soon as he can, and with as much openness and transparency as possible."

The White House has not received or been briefed on the report, spokeswoman Sarah Sanders said, adding, "we look forward to the process taking its course."

Representative Steve Scalise, the No. 2 House Republican and a strong ally of the president, expressed confidence the report would not find collusion with Russia. — Reuters