Russia carried out a comprehensive cyber-campaign to upend the U.S. presidential election, an operation that was ordered by Russian President Vladi­mir Putin and “aspired to help” elect Donald Trump by discrediting his Democratic rival, Hillary Clinton, U.S. intelligence agencies concluded in a report released Friday.

The Washington Post reports that details of the submissions by US Intelligence depict Russian interference as unprecedented in scale, saying that Moscow’s assault represented “a significant escalation in directness, level of activity, and scope of effort” beyond previous election-related espionage.

The campaign was ordered by Putin himself and initially sought primarily to undermine public faith in the U.S. democratic process, “denigrate Secretary Clinton” and harm her electoral prospects. But as the campaign proceeded, Russia “developed a clear preference for President-elect Trump” and repeatedly sought to elevate him by “discrediting Secretary Clinton and publicly contrasting her unfavorably to him.”

The document represents an extraordinarily direct and detailed account of a long-standing U.S. adversary’s multi-pronged intervention in a fundamental pillar of American democracy.

Trump emerged from a briefing on the report by the nation’s top intelligence officials Friday seeming to acknowledge for the first time at least the possibility that Russia was behind election-related hacks. But he offered no indication that he was prepared to accept U.S. spy agencies’ conclusion that Moscow sought to help him win.

U.S. intelligence agencies released a declassified version of their report on Russian intervention in the 2016 U.S. election on Jan. 6, just hours after President-elect Donald Trump was briefed by American officials. (Video: Peter Stevenson: The Washington Post/Photo: Jabin Botsford/The Washington Post)

Instead, Trump said in a statement issued just minutes after the high-level meeting ended that whatever hacking had occurred, “there was absolutely no effect on the outcome of the election.”

Trump’s statement seemed designed to create the impression that this was the view of the intelligence officials, including Director of National Intelligence James R. Clapper Jr. and CIA Director John Brennan, who had met with him.

But weighing whether Russia’s intervention altered the outcome of the 2016 race was beyond the scope of the review that the nation’s spy agencies completed this week. And Clapper testified in a Senate hearing Thursday that U.S. intelligence services “have no way of gauging the impact . . . it had on the choices the electorate made. There’s no way for us to gauge that.”

Trump’s statement came after his first face-to-face encounter with the leaders of intelligence agencies whose work he has repeatedly disparaged. Others who took part in the meeting included FBI Director James B. Comey and National Security Agency chief Adm. Mike Rogers.

All four of the spy chiefs have endorsed a classified report that was briefed to Trump and circulated in Washington this week that concludes that Russia used a combination of aggressive hacking, propaganda and “fake news” to disrupt the 2016 U.S. presidential race.

Trump appeared to acknowledge that hacking of Democratic and Republican computer networks had occurred, but was apparently not prepared to accept the consensus view of U.S. spy services that Russia sought to help him win.

“I had a constructive meeting and conversation with the leaders of the intelligence community,” Trump said. He acknowledged that “Russia, China, other countries, outside groups and people are consistently trying to break through the cyber-infrastructure of our government institutions, businesses and organizations including the Democrat National Committee.”