Washington: A united front of top intelligence officials and senators from both parties on Thursday forcefully reaffirmed the conclusion that the Russian government used hacking and leaks to try to influence the presidential election, directly rebuffing President-elect Donald Trump’s repeated questioning of Russia’s role.

They suggested that the doubts Trump has expressed on Twitter about the agencies’ competence and impartiality were undermining their morale.

“There’s a difference between scepticism and disparagement,” James R. Clapper Jr., the director of national intelligence, said at a hearing of the Senate Armed Services Committee on the Russian hacks. He added that “our assessment now is even more resolute” that the Russians carried out the attack on the election.

The Senate hearing was the prelude to an extraordinary meeting scheduled for Friday, when Clapper and other intelligence chiefs will repeat for Trump the same detailed, highly classified briefing on the Russian attack that President Barack Obama received on Thursday. In effect, they will be telling the president-elect that the spy agencies believe he won with an assist from President Vladimir Putin of Russia.

Then Trump will have to say whether he accepts the agencies’ basic findings on Russia’s role — or holds to his previous contention that inept, politicised American spies have gotten the perpetrator of the hacking wrong. That would throw the intelligence agencies into a crisis of credibility and status with few, if any, precedents.

In a pair of Twitter posts early on Thursday, Trump appeared to back away from the scorn he had previously expressed for the intelligence agencies’ work, as well as from his embrace of Julian Assange, the founder of WikiLeaks, which released most of the hacked emails of Democratic officials.

“The dishonest media likes saying that I am in agreement with Julian Assange — wrong,” Trump wrote. “I simply state what he states, it is for the people to make up their own minds as to the truth. The media lies to make it look like I am against ‘Intelligence’ when in fact I am a big fan!”

But on Thursday night, the president-elect returned to Twitter and appeared to underscore his doubts about the Federal Bureau of Investigation’s (FBI’s) investigation of the hacking.

“The Democratic National Committee would not allow the FBI to study or see its computer info after it was supposedly hacked by Russia,” he wrote, a day after a report by BuzzFeed on the issue. “So how and why are they so sure about hacking if they never even requested an examination of the computer servers? What is going on?”

Early next week, the public will get its fullest information to date on the evidence the agencies have to support their contention that Putin’s government used the hacked emails to hurt Hillary Clinton’s campaign and help Trump’s. Clapper said he would “push the envelope” to include as much detail as possible in the unclassified version of the intelligence agencies’ report on the Russian operation.

The hacking, he added, was only one part of that operation, which also included the dissemination of “classical propaganda, disinformation, fake news.”

The Senate hearing on Thursday, devoted to foreign cyberthreats, was unusual as much for its context as its content — a public, bipartisan display of support for the intelligence community that seemed aimed, at times, at an audience of one. Though Clapper and most Republican senators were careful to avoid antagonising the president-elect directly, the hearing spoke to the rift Trump has threatened to create between the incoming administration and the intelligence officials assigned to inform it.

Sen. John McCain, R-Arizona, the chairman of the committee, said the purpose of the gathering was “not to question the outcome of the presidential election” but to move forward with a full understanding of what had happened.

Repeatedly, though, McCain and his colleagues seemed to undercut Trump’s past messages of support for Russia, and for Assange of WikiLeaks.

“Do you think there’s any credibility we should attach to this individual?” McCain asked.

“Not in my view,” Clapper said. Another witness at the hearing, Adm. Michael S. Rogers, the head of the National Security Agency and US Cyber Command, said he agreed.

The intelligence director said he welcomed sceptical questioning from Trump, allowing that the intelligence community was “not perfect.”

Sen. Joe Donnelly, D-Indiana, told Clapper that in the conflict between the intelligence agencies and Assange over Russian responsibility for the attack, “We’re on your side every time.” He asked Clapper to convey his level of confidence in attributing the election attack to Russia, rather than “someone in his basement.”

“It’s, uh, very high,” the laconic intelligence director replied.

At one point, Sen. Claire McCaskill, D-Missouri, wondered aloud “who benefits from a president-elect trashing the intelligence community.” McCaskill said there would be “howls from the Republican side of the aisle” if a Democrat had spoken about intelligence officials as Trump had.

Perhaps the closest to a defence of Trump came from Sen. Tom Cotton, R-Arkansas. Decrying “imprecise language” stating that Russia “hacked the election”, Cotton asked Clapper to confirm that the actual balloting was not affected.

Cotton also suggested that the conventional wisdom that Putin favoured Trump over Clinton might be wrong. Trump promised a stronger military and more US oil and gas production — policies Cotton suggested would not be to Russia’s advantage.

Sen. Lindsey Graham, R-South Carolina, criticised the Obama administration for its response to the Russian attack. He said the White House had lobbed mere “pebbles” in retaliation for the interference.

“When it comes to interfering with our election, we better be ready to throw rocks,” he said.