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 U.S. 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.