Donald Trump on Monday issued his most forceful pushback to date against claims that Russian hacks of Hillary Clinton's campaign chairman and the Democratic National Committee were carried out in order to help Trump win the presidential election.

'Can you imagine if the election results were the opposite and WE tried to play the Russia/CIA card. It would be called conspiracy theory!' the president-elect wrote on Twitter.

Trump senior adviser Kellyanne Conway agreed, saying on 'Good Morning America' that liberal partisans were blaming Moscow for their defeat instead of being critical of Clinton's shortcomings.

Trump went a step further, tweeting his doubt that Russia was behind the infamous cyber intrusion in the first place.

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Donald Trump dismissed CIA claims that Russian hacks were intended to help him win the election, saying it would be considered a 'conspiracy theory' if the tables were turned

Trump tweeted Monday that it's 'hard' to know who hacked Democrats' emails before the November election since they weren't caught in the act

'Unless you catch "hackers" in the act, it is very hard to determine who was doing the hacking. Why wasn't this brought up before election?' he asked.

Senate Majority Leader Mitch McConnell said Monday that he supports calls for a congressional investigation into whether Russia interfered in the Nov. 8 election.

'Obviously any foreign breach of our cybersecurity measures is disturbing, and I strongly condemn any such efforts,' McConnell said during a press conference at the Capitol.

Foreign meddling in U.S. elections 'simply cannot be a partisan issue,' he added, saying that the Senate's existing committees can handle the job.

'It's an important subject and we intend to review it on a bipartisan basis,' McConnell said, before adding that 'the Russians are not our friends.'

Trump said on 'Fox News Sunday that Democratic critics were grasping at straws to explain the beating Clinton took on Election Day, and the spinner had landed on Russia.

The CIA told senators in a secret meeting that they believed hacks on Democratic emails in the election were intended to aid Trump's victory, but the FBI disagrees

'I think it's ridiculous. I think it's just another excuse. I don't believe it,' he said.

'I don't know why, and I think it's just – you know, they talked about all sorts of things. Every week it's another excuse.'

Trump spokesman Jason Miller told reporters Monday morning that 'this overall narrative that's in the news right now' about Russia 'is an attempt to try to delegitimize President-elect Trump's win. That really seems to be the – what's going on here.'

'First after the election it was the recount nonsense. Then it was discussions of the popular vote. Now it's the anonymous off-the-record sources with conflicting information, trying to raise other issues,' he said.

Trump on Sunday also blamed Democrats for reports about a reported CIA briefing before a group of U.S. senators, which purportedly included an assessment of Russia's role in the hacks.

'I'm not sure [the CIA] put it out,' he said. 'I think the Democrats are putting it out because they suffered one of the greatest defeats in the history of politics, and frankly I think it’s ridiculous.'

A senior FBI official doubted the CIA's claim, saying there wasn't enough proof that Russia had a specific aim or favorite in the presidential race

Trump said on 'Fox News Sunday' that claims he was elected as a result of Russian hacks were 'ridiculous. I think it's just another excuse. I don't believe it'

The Washington Post reported over the weekend that the CIA believes Russia's specific goal was to help elect Trump.

Previously, the Agency had suggested that the hacks might have been intended to more generally undermine the public's faith in the electoral system, without favoring a particular candidate.

That, it emerged Saturday, is the view the FBI currently holds.

In a secret House Intelligence Committee meeting, a senior FBI official refused to conclusively say that the Russian hacks into Democratic emails were intended to help Trump, an official who was in that briefing told the Post.

'It was shocking to hold these [CIA] statements made about Russian intentions and activities, and to hear this guy basically saying nothing with certainty and allowing that all was possible,' said the official, who spoke on condition of anonymity.

Despite repeated prodding for two hours by Republicans and Democrats in the committee, the FBI counterintelligence official would not back the CIA's new direction.

While his CIA equivalent had been 'direct and bald and unqualified' about Russia's scheme to aid the new president-elect, the FBI agent's statements wee 'fuzzy' and 'ambiguous.'

There just wasn't enough evidence of intention, the FBI said.

The hacks, including one on the emails of Clinton campaign chair John Podesta (pictured) and another on DNC staff, led to devastating publicity for the Democrats during the election

'There's no question that [the Russians'] efforts went one way, but it's not clear that they have a specific goal or mix of related goals,' a US official who was at the meeting said.

Part of the problem is the way that two two organizations view the disparate and incomplete evidence available to law enforcement and intelligence operatives.

'The FBI briefers think in terms of criminal standards - "Can we prove this in court?"' one official said.

'The CIA briefers weigh the preponderance of intelligence and then make judgment calls to help policymakers make informed decisions.

'High confidence for them means "We're pretty damn sure." It doesn't mean they can prove it in court.'

Former U.S. Ambassador to the United Nations John Bolton said Sunday that it's possible the cyber attacks were 'false flag' operations, since the digital intruders left telltale signs pointing to Russian intelligence.

Bolton, who is considered a potential deputy secretary of state appointee, noted that other hacks attributed to the Russians have left no 'fingerprints' behind.

Trump said Sunday that he would be making 'changes at the top' in the intelligence community, 'because we have our people and they have their people' – adding that 'I have great respect for them.'

CIA director John Brennan (pictured in 2014) may be looking for a new job when Trump takes over, as the President-elect has promised 'changes at the top'

President Obama has ordered an investigation into the Russian hacks, to be completed before he leaves office next month.

And a bipartisan group of lawmakers have demanded that it be accompanied by a joint congressional investigation into the cyber-attacks.

In a statement released Saturday morning, Republican Senators John McCain of Arizona and Lindsey Graham of South Carolina along with Democrats Jack Reed of Rhode Island and Chuck Schumer of New York, asked Congress 'to examine these recent incidents thoroughly.'

'This cannot become a partisan issue. The stakes are too high for our country. We are committed to working in this bipartisan manner,' they added.

The group also called for solutions to be devised to defend against future cyber attacks.

The mid-election hacks resulted in leaks of 19,252 emails and 8,034 attachments from the DNC that showed staffers mocking and apparently undermining Bernie Sanders' campaign to be the Democratic candidate.

A second hack saw emails being leaked from the account of Clinton campaign chair John Podesta, including some that apparently discussed payments to the Clinton Foundation in exchange for meetings with Bill Clinton.