President-elect Donald Trump has rejected a CIA finding that Russia sought to influence the US election on his behalf, labelling the assessment ridiculous.
Instead Trump blamed "very embarrassed" Democrats for the public release of the assessment.
Trump's rejection follows the CIA releasing its conclusion that Russia sought to influence the US election on Trump's behalf.
"I think it's ridiculous," Trump said in an interview with Fox News Sunday. "I think it's just another excuse. I don't believe it ... No, I don't believe it at all."
Trump's comments are in stark opposition to the CIA conclusion which found individuals with connections to the Kremlin provided WikiLeaks with thousands of hacked emails from the Democratic National Committee.
Trump also revealed he is not interested in getting daily intelligence briefings - an unprecedented rejection of the nation's massive and sophisticated intelligence apparatuses.
"I'm, like, a smart person. I don't have to be told the same thing in the same words every single day for the next eight years," Trump said.
The finding by the CIA alarmed politicians, including Senate Armed Services Committee chairman John McCain who said he planned to put Senator Lindsay Graham, a staunch Trump critic, in charge of investigating the claim.
Trump's incoming chief of staff, Reince Priebus also shrugged off allegations that Russia helped Trump win.
He said: "The Russians didn't tell Clinton to ignore Wisconsin and Michigan," in reference to the two states she was expected to win that went to Trump.
"She lost the election because her ideas were bad. She didn't fit the electorate. She ignored states that she shouldn't have and Donald Trump was the change agent," Priebus said on ABC's This Week.
He insisted Trump's win "had nothing to do with the Russians".
McCain, along with top Republican senator Lindsey Graham, joined leading Democrats in calling for greater public disclosure about the cyber attacks.
"This cannot become a partisan issue. The stakes are too high for our country," they said in a joint statement with Chuck Schumer, the incoming Democratic leader in the Senate, and Democrat Jack Reed.
They pledged to work across party lines to have the incidents investigated, but other Republicans said the evidence does not support the conclusions that the Russian meddling was aimed at helping Mr Trump.
Adam Schiff, the ranking Democrat on the House Intelligence Committee, said the hacking was definitely the work of the Russians.
"This was not China. This wasn't a 400 pound guy in New Jersey or anyone else," Schiff said, mocking similar comments Trump has made.
"This was the Russians."
Trump's willingness to disregard the intelligence community's "overwhelming evidence" was "extraordinarily damaging," he said.
It wouldn't be the first time Russia has been accused of interference in the US election process.
US intelligence has previously linked Russia to leaks of damaging emails from Democratic candidate Hillary Clinton's campaign but saw it as a broad bid to undermine confidence in the US political process.
On Friday, however, The Washington Post reported that the CIA has since concluded that the aim of the cyber intrusions was to help Trump win the election.
The New York Times quoted a senior administration officials as saying there was "high confidence" that the Russians hacked both the Democratic and Republican National Committees, but leaked only documents damaging to Clinton through WikiLeaks.
Reince Priebus, the Republican National Committee chairman and Trump's incoming White House chief of staff, said the FBI had investigated and told the RNC it had not been hacked.
WikiLeaks founder Julian Assange has denied links with Russia's government and Trump dismissed the intelligence reports, asserting there is "great confusion" over the issue within the spy agencies.
"Nobody really knows," he said. "They have no idea if it's Russia or China or somebody. It could be somebody sitting in a bed some place. They have no idea."
Trump suggested he had little confidence in the US intelligence agencies and would clean house once in office.
"We're going to have different people coming in because we have our people, they have their people."
The controversy over the CIA's revelation on Friday comes as key congressional Republicans also questioned consideration of Exxon Mobil CEO Rex Tillerson - who has close business ties with Moscow - as head of the State Department.
Asked whether he's rejecting valuable intelligence on Fox News Sunday, Trump remained defiant.
"I get it when I need it," he said of the top-secret briefings sessions, adding that he's leaving it up to the briefers to decide when a development represents a "change" big enough to notify him.
McCain also raised questions about Tillerson's business relationship with Russian President Vladimir Putin.
However it remains unclear if Tillerson will be nominated and as of last night had not formally been offered the job, according to a person with knowledge of the process who spoke on condition of anonymity.
Exxon steadily expanded its Russian business on Tillerson's watch even as its rivals faced expropriation and regulatory obstacles.
In 2013, Putin bestowed the Order of Friendship on Tillerson.
"Maybe those ties are strictly commercial and got to do with his business in the oil business. Fine," McCain told CBS Face the Nation.
And "we'll give him a fair hearing. But is it a matter of concern? Certainly it should be a matter of concern."
McCain wasn't alone in raising questions about whether there would be enough blowback to sink a Tillerson nomination.