Donald Trump has said it would be "stupid" for the United States not to develop a close relationship with Russia, despite claims it tried to influence his election victory.
US intelligence agencies have accused Russian President Vladimir Putin of launching an "influence campaign" to damage Democratic presidential candidate Hillary Clinton.
The report, issued on Saturday, said Russia showed a "clear preference" for Donald Trump and carried out cyber attacks which included hacking Democratic Party computers and issued propaganda to both boost Trump's chances and undermine confidence in American democracy.
The report, ordered by President Barack Obama, concluded that Putin had "aspired to help Trump's election chances when possible by discrediting Clinton and publicly contrasting her unfavourably to him".
Trump insisted on Saturday that foreign meddling had "absolutely no effect" on the outcome of the election, and declined to say whether he believed Russia was behind the hacks.
Yesterday he said that only "stupid" people would criticise the US for having a good relationship with Russia.
In the latest of a series of tweets the President-elect wrote: "Having a good relationship with Russia is a good thing, not a bad thing. Only 'stupid' people, or fools, would think that it is bad!"
Another said: "We have enough problems around the world without yet another one. When I am President, Russia will respect us far more than they do now and both countries will, perhaps, work together to solve some of the many great and pressing problems and issues of the WORLD!"
The US intelligence report, reflecting the joint assessment of the CIA, FBI and the National Security Agency, suggested that some of these early tipoffs about Russia's activities came from voice intercepts, computer traffic or human sources outside the US.
The President-elect was briefed by senior intelligence officials for nearly two hours on Saturday, describing the briefing in a statement as "a constructive meeting and conversation with the leaders of the intelligence community".
Among those identified by US intelligence as taking part in the hacking is a young Russian computer expert identified as Alisa Shevchenko, whose companies Esage Lab and ZOR are among those now included on an American sanctions list.
Shevchenko, who is currently based outside the Thai capital Bangkok, has denied having knowingly worked for the Russian Government.
The report did not draw any conclusion as to what effect the Russian hacking had on the election, saying it was beyond its responsibility to analyse American "political processes" or public opinion.
The issue of Russia's relations with Western Europe became even more fraught yesterday when Sweden's most respected foreign policy institute accused it of using underhand methods in an "information war", including fake news, counterfeit documents, and other disinformation, to influence Swedish decision-making.
The report by Martin Kragh, from the Swedish Institute of International Affairs, said Russia was using "active measures" in its information war against Sweden, in a bid to steer it away from joining Nato.
Russia has long opposed either Sweden or Finland joining Nato and has threatened to mass troops on the Finnish border if it moves to join the military alliance.
Meanwhile the former deputy chief of the CIA has warned that allied intelligence agencies may shy away from sharing information with the CIA if they feel the agency does not have the confidence of Trump.
In a scathing article in the New York Times, Michael Morell warned that Trump's public disparagement of the CIA was likely to damage its relationship with its overseas counterparts.
"Why would a foreign intelligence service take the CIA seriously when the American president doesn't?" he wrote.