US special counsel Robert Mueller has said he believed he was constitutionally barred from charging Donald Trump with a crime but pointedly emphasised that his Russia report did not exonerate the president.

“If we had had confidence that the president clearly did not commit a crime, we would have said so,” Mueller said. “We did not, however, make a determination as to whether the president did commit a crime.”

Mueller cautioned politicians who have been negotiating for his public testimony that he would not go beyond his report in the event he appears before Congress.

But he also signalled that Congress was the proper venue, not the criminal justice system, for deciding whether action should be taken against the president in connection with allegations that Trump and aides obstructed the investigation of Russian interference to help the Republican during his 2016 election campaign. Trump, who has repeatedly and falsely claimed that Mueller’s report cleared him of obstruction of justice, modified that contention somewhat shortly after the special counsel’s remarks. He tweeted: “There was insufficient evidence and therefore, in our Country, a person is innocent. The case is closed!”

The National:

Mueller’s comments were his first public statements since his appointment as special counsel two years ago. His remarks, one month after the public release of his report on Russian efforts to help Trump win the presidency, appeared intended to both justify the legitimacy of his investigation against complaints by the president and to explain his decision to not reach a conclusion on whether Trump had obstructed justice. Indicting Trump, he said firmly, was “not an option” in light of a Justice Department legal opinion that says a sitting president cannot be charged. But, he said, the absence of a conclusion should not be mistaken for an exoneration of the president.

“The opinion says the constitution requires a process other than the criminal justice system to formally accuse a sitting president of wrongdoing,” Mueller said, referring to the Justice Department legal opinion.

That would shift the next move, if any, to Congress, and the chairman of the House Judiciary Committee, which would investigate further or begin any impeachment effort, commented quickly.

It falls to Congress to respond to the “crimes, lies and other wrongdoing of President Trump - and we will do so”, said New York Representative Jerrold Nadler.

Trump has blocked the committee’s subpoenas and other efforts to dig into the Trump-Russia issue, insisting Mueller’s report has settled everything.