US President-elect Donald Trump has called a recent CIA assessment of Russian hacking "ridiculous".
Mr Trump also says he is not interested in getting daily intelligence briefings - an unprecedented rejection of the nation's massive and sophisticated intelligence apparatus.
The president-elect's remarks come as key congressional Republicans joined Democrats in demanding a bi-partisan investigation into the Kremlin's activities and questioned consideration of Exxon Mobil CEO Rex Tillerson - who has close business ties with Moscow - as head of the State Department.
Asked whether he is rejecting valuable intelligence on Fox News Sunday, Mr Trump was defiant.
"I get it when I need it," he said of the top-secret briefings sessions, adding that he is leaving it up to the briefers to decide when a development represents a "change" big enough to notify him. "I don't have to be told the same thing in the same words every single day for the next eight years."
The CIA has concluded with "high confidence" that Russia sought to influence the US election on behalf of Mr Trump. The finding alarmed legislators, including Senate Armed Services Committee Chairman John McCain who said he planned to put senator Lindsay Graham, a staunch critic of Mr Trump, in charge of investigating the claim.
Mr McCain has vowed to scrutinise Mr Tillerson's business relationship with Russia President Vladimir Putin, if Mr Tillerson is nominated. Exxon steadily expanded its Russian business on his watch even as its rivals faced expropriation and regulatory obstacles. In 2013, Mr Putin bestowed the Order of Friendship on Mr Tillerson.
"Maybe those ties are strictly commercial and got to do with his business in the oil business. Fine," Mr McCain said. "And "we'll give him a fair hearing. But is it a matter of concern? Certainly it should be a matter of concern."
Mr McCain was not alone, raising questions about whether there would be enough of a backlash to sink a nomination for Mr Tillerson.
"Being a 'friend of Vladimir' is not an attribute I am hoping for from a #SecretaryOfState," tweeted Florida Republican senator Marco Rubio, Mr Trump's former campaign rival and a member of the Senate Foreign Relations Committee.
Pennsylvania Democratic senator Bob Casey said the developments "raise serious questions about whether the incoming administration will adequately stand up to Russia's aggression."
Mr Trump said Mr Tillerson's relationship with Moscow was a selling point.
"A great advantage is he knows many of the players, and he knows them well. He does massive deals in Russia. He does massive deals for the company," Mr Trump told Fox News in an interview broadcast on Sunday. Senate Foreign Relations Committee Chairman Bob Corker is impressive, and former bitter rival Mitt Romney is still in the mix, Mr Trump added.
"These are all very different types of people," he said. "But when you ask me about Rex, I mean, he's a world-class player. There's no question about it."
Mr Trump also rejected the CIA's conclusion that Russia tried to interfere with the presidential election and blamed "very embarrassed" Democrats for the public release of the assessment. The Washington Post first reported the CIA finding on Friday.
"It's ridiculous," Mr Trump said of the CIA's assessment. He added, however, that he does not necessarily oppose President Barack Obama's order for a review of campaign-season hacking. "If you're going to do that, I think you should not just say 'Russia'. You should say other countries also, and maybe other individuals."
The White House has said the probe would focus on any breaches by other countries, and past elections.
Mr Trump's incoming chief of staff, Reince Priebus, said Mr Tillerson's nomination is not a done deal but shrugged off allegations that Russia helped Mr Trump win.
He said: "The Russians didn't tell Clinton to ignore Wisconsin and Michigan," two states she was expected to win that went instead for Mr 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," Mr Priebus said. Mr Trump's win, he added, "had nothing to do with the Russians".
On other matters, Mr Trump said he is leaving his worldwide business empire to his executives and children, vowing, that he will "have nothing to do with management". He is expected to discuss the arrangement at a news conference on Thursday.
He also said he is "studying" the Paris climate agreement to reduce carbon emissions. But he does not want the agreement to put the US "at a competitive disadvantage with other countries".