The Director of National Intelligence, James Clapper, has told a congressional committee Russia hacked Democratic Party institutions and operatives and disseminated propaganda and fake news aimed at influencing the November presidential election.
James Clapper says Russia's President Vladimir Putin ordered the hacking and says the motive will be revealed next week.
The United States is yet to prove its case against Russia but James Clapper says he's never encountered a more aggressive or direct campaign to interfere in the election process.
Clapper: "This was a multi-faceted campaign. So, the hacking was only one part of it and it also entailed classical propaganda, disinformation, fake news."
Senator Jack Reed: "Does that continue?"
Clapper: "Yes."
A report on the alleged hacking has been provided to President Obama and the unclassified version is due to be made public next week.
James Clapper says it's clear Russia has become more aggressive.
"Russia has clearly assumed an even more aggressive cyber-posture by increasing cyber-espionage operations, leaking data stolen from these operations, and targeting critical infrastructure systems."
The Chairman of the Armed Services Committee, Senator John McCain, asked James Clapper whether Russia's actions amounted to a direct attack on the United States.
"First, we cannot say .... They did not change any vote tallies or anything of that sort. We have no way of gauging the impact ... certainly the intelligence community can't gauge the impact it had on the choices that the electorate made. There is no way for us to gauge that. Whether or not that constitutes an act of war, I think, is a very heavy policy call that I don't believe the intelligence community should make but it certainly would, in my view, carry great gravity."
President-elect Donald Trump is receiving a briefing on Friday on the official report given to Barack Obama.
Mr Trump has repeatedly expressed doubt Russia interfered in the election, using Twitter to seize on comments by Wikileaks founder Julian Assange, who told Fox News Russia was not the source of the hacked emails written by John Podesta, the former head of Hillary Clinton's campaign.
"We published several Podesta emails which shows Podesta responding to a phishing email. Now, how did they respond? Podesta gave out that his password was the word 'password', his own staff said 'this email that you've received, this is totally legitimate.' So this is something a 14 year-old kid -- a 14 year-old kid -- could have hacked Podesta that way."
Senator McCain asked the intelligence chiefs for their assessment of Julian Assange.
(McCain) "General Clapper, I just have to mention the name, Mr. Assange, has popped up and I believe that he is one who is responsible for publishing names of individuals that work for us that put their lives in direct danger. Is that correct?"
(Clapper) "Yes, he has."
(McCain): "And do you think there is any credibility we should attach to this individual, given his record of--?"
(Clapper): "Not in my view."
(McCain): "Not in your view. Admiral Rogers?"
(Rogers): "I second those comments."
Donald Trump says he doesn't agree with Julian Assange and was simply drawing attention to the Fox News interview to let people make up their own minds as to the truth.
He says the media lies to make it appear he's against intelligence agencies when instead he's a big fan.
Mr Trump has just named former US Senator Dan Coats to replace James Clapper when he steps down as US intelligence chief on January 20.
