WASHINGTON • US House Democrats have formally requested that Attorney-General William Barr hand over special counsel Robert Mueller's report - which found no collusion between Mr Donald Trump's 2016 presidential campaign team and Russia - to Congress by April 2.

The Democratic chairmen of six House committees, in a letter to Mr Barr on Monday, said his four-page summary of the Mueller report "is not sufficient for Congress, as a co-equal branch of government", to examine Mr Trump's conduct.

They also asked Mr Barr to begin transmitting the underlying evidence and the materials used to prepare the special counsel's report starting on April 2. "Congress must be permitted to make an independent assessment of the evidence regarding obstruction of justice," said the committee leaders.

They said they also want to examine the evidence on Mr Trump and Russia's interference in the 2016 presidential election.

They did not address what actions they might take if Mr Barr refused or missed the deadline, though they said they were prepared to discuss whether some materials should be withheld.

Those signing the letter include judiciary committee chairman Jerry Nadler, intelligence committee chairman Adam Schiff, oversight and reform committee chairman Elijah Cummings and foreign affairs committee chairman Eliot Engel.

They added in the letter that they had no reason to question Mr Mueller's conclusions, "but it is vital for national security purposes that Congress be able to evaluate the full body of facts and evidence collected and evaluated by the special counsel, including all information gathered of a counter-intelligence nature".

The sweeping demand could set up a showdown between Congress and the Justice Department - as part of the executive branch of government - over what parts of Mr Mueller's findings, including highly sensitive law enforcement and classified material, should be released.

Financial services committee chairman Maxine Waters, who also signed the letter, said Democrats want to learn of Mr Mueller's probe, "what work went into it, what was considered, what was not considered, and why?"

After the letter was released, Mr Cummings said he had "full faith and confidence in Mueller", but pointed out that the special counsel did not reach a conclusion on whether Mr Trump obstructed justice. Mr Barr had found that there was not enough evidence to form an obstruction case.

Mr Cummings said he believed that "what Mueller was saying by not making a finding with regard to obstruction was that he wanted Congress to take a look at it" and see if it can reach a decision.

Meanwhile, Mr Trump's inner circle has piled in on the US news media, which has been plunged into soul-searching over its coverage of Mr Mueller's two-year probe, which failed to show collusion.

With the United States' political landscape reset by the bombshell findings, some continued to defend aggressive reporting of a story that is still unfolding, while the White House on Monday wasted little time in sharpening its attacks.

"I think Democrats and the liberal media owe the President and they owe the American people an apology," said White House spokesman Sarah Sanders on NBC.

But well beyond the Trump camp, there was an acknowledgement that the summary of Mr Mueller's conclusions released on Sunday risked badly damaging the credibility of many news outlets in the eyes of the public.

Ms Deborah Potter, a former CBS News correspondent who now runs media and ethics training programmes, said much cable coverage was "based on speculation because there were zero leaks from Mueller".

She also stressed that "many responsible news organisations were giving the correct impression" of where the probe was headed.

But she warned that the heightened scrutiny triggered by Mr Mueller's findings would make it harder for the sector to regain the public's trust, badly eroded in recent years.

"We've seen a rebound in general trust in the media, but the partisan divide is as deep as ever," she said. "Republicans distrust the media by a wide margin and that is a symbol of where things stand, and troubling for democracy."

BLOOMBERG, AGENCE FRANCE-PRESSE

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