Special Counsel Robert Mueller has handed in a keenly awaited report on his investigation into Russia's role in the 2016 presidential election and any potential wrongdoing by US President Donald Trump, the Justice Department said on Friday. Mr Mueller submitted the report to Attorney General William Barr, the top US law enforcement official, the department said. The report was not immediately made public - Mr Barr will have to decide how much to disclose - and it was not known if Mr Mueller found criminal conduct by Mr Trump or his campaign, beyond the charges already brought against several aides. Mr 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. But it was not immediately clear whether the special counsel had any sealed indictments that could later be disclosed. Mr Mueller, a former FBI director, had been examining since 2017 whether Mr Trump's campaign conspired with Moscow to try to influence the election and whether the Republican president later unlawfully tried to obstruct his investigation. White House press Secretary Sarah Sanders said the neither the President nor his team have been briefed on the report. "The next steps are up to Attorney General Barr, and we look forward to the process taking its course. The White House has not received or been briefed on the Special Counsel’s report." In a letter from Mr Barr to the House Judiciary committee, the US Attorney General said he may be able to disclose to the committee some conclusions as soon as this weekend. The chair of the committee released the letter on Twitter. The Democratic leadership in Congress released a statement calling on Mr Barr to make the content of the report public. "It is imperative for Mr Barr to make the full report public and provide its underlying documentation and findings to Congress," House Speaker Nancy Pelosi and Senator Chuck Schumer said in a statement. They said that neither President Trump, nor his lawyers or his staff should be allowed "any ‘sneak preview’ of Special Counsel Mueller's findings or evidence, and the White House must not be allowed to interfere in decisions about what parts of those findings or evidence are made public".