Robert Mueller has agreed to testify before US Congressional committees after being issued with subpoenas, Democrats have said.

The former special counsel will testify on July 17 about the Trump-Russia report he issued in April, House Judiciary Committee chairman Jerrold Nadler and House Intelligence Committee chairman Adam Schiff said in a joint statement.

Mr Mueller painstakingly documented Russian efforts to boost Mr Trump's campaign and undermine that of his Democratic rival Hillary Clinton for the 2016 election.

The Herald:

The former FBI director's report, which shadowed the 45th presidency for more than two years, stopped short of saying the efforts contributed to Mr Trump's victory.

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Mr Mueller has been hesitant to speak about the investigation beyond a public statement he issued in late May.

He pointedly rejected Mr Trump's claims - repeated almost daily - that the special counsel's investigation cleared him of criminal activity and was a "witch hunt".

The Herald:

Mr Mueller emphasised that he had not exonerated Mr Trump on the question of whether he obstructed justice, but said charging the president with any crime was "not an option" because of US justice department rules.

"If we had had confidence that the president clearly did not commit a crime, we would have said so," Mr Mueller declared.

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Mr Mueller has made clear that his team never considered indicting Mr Trump because the Justice Department prohibits the prosecution of a sitting president. He and others have indicated that the next move, if any, is up to Congress, which has the power of impeachment.

It falls to Congress to respond to the "crimes, lies and other wrongdoing of President Trump - and we will do so", Mr Nadler said after the special counsel's public statement in May.

Mr Trump has previously blocked US house committees' subpoenas and other efforts to dig into the Trump-Russia issue, insisting Mr Mueller's report has settled everything.

"The American public deserves to hear directly from you about your investigation and conclusions," the committee chairmen said in a letter accompanying the Mueller subpoenas.

Democrats want Mr Mueller to testify as they consider the possibility of impeaching Mr Trump.

The president seemingly reacted to the news of Mr Mueller's planned testimony by tweeting: "Presidential Harassment!"

Attorney General William Barr has decided on his own that the evidence of the Mueller report was not sufficient to support an obstruction charge against Mr Trump.

The Justice Department has declined to comment on Mr Mueller's future appearance before House committees.