US officials discover MORE Russian cyberattacks over the past few days in the wake of revelations over election hacking 

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US government officials have been notified of new cases of attempted or potentially successful cyber intrusions amid claims that Russians hacked computers to influence the presidential election outcome. 

A top adviser to President-elect Donald Trump believes the Russians were involved in hacking into US computers in order to influence November's election -contradicting the view held by the incoming administration. 

And a report from CBS News suggests the hacks were more extensive than previously thought since the US released a report on Thursday on election-related cyber attacks. 

Former CIA director James Woolsey, an adviser to Trump on national security issues, told CNN that determining who was behind the hacks is difficult, but that he believes the Russians were involved.   

Russian President Vladimir Putin makes his New Year's address to the nation in Moscow's Kremlin

Former CIA director James Woolsey, an adviser to Trump on national security issues, believes the Russians were involved in hacking into US computers in order to influence the outcome of the election

'I think the Russians were in there, but it doesn't mean other people weren't, too', said Woolsey. 'It's often not foolproof to say who it is because it is possible and sometimes easy to hide your tracks. There's lots of tricks'. 

Woolsey's comments come even as Trump and his administration cast doubts on the assessment by the intelligence community in October that Russia was behind the hacks. 

Trump expressed skepticism on New Year's Eve, saying, 'I know a lot about hacking. And hacking is a very hard thing to prove. So it could be somebody else. And also - I know things that other people don't know - and so they cannot be sure of the situation'. 

Trump's incoming press secretary, Sean Spicer, said the President-elect is privy to 'classified information, intelligence reports, he gets briefed by his national security team on a daily basis'. 

President-Elect Donald Trump and his administration disagree with Woolsey 

Sean Spicer, Trump's incoming press secretary, defended the president-elect's claim to 'know a lot about hacking' and Russia

It's unclear where Trump and his administration get their intelligence reports because all US intelligence agencies are in agreement that the Russian government conducted cyberattacks prior to and during the presidential election. 

Spicer said Trump would await the results of the investigation ordered by President Barack Obama as he insisted that the assessments published so far did not constitute a final report. 

After US government officials recently connected with Vermont's electric grid, it was confirmed that newly identified 'digital fingerprints' indicate Russia was behind the hacks. 

The hacks have been traced to specific keyboards, which featured Cyrillic characters (Russia's alphabet), that were used to construct the malware code used in operation 'Grizzly Steppe', the name Homeland Security applied to a Russian campaign linked to the intrusions.  

This code was found on a Burlington Electric Department laptop. The Burlington, Vermont, utility company detected the malware in December in a laptop not connected to its grid systems.

Department of Homeland Security analysts haven't been able to determine the intent behind the hack of the Burlington, Vermont, electric grid in December

Department of Homeland Security analysts haven't been able to determine the intent behind the incident, but the power grid doesn't appear to have been compromised.

Officials won't reveal the details or the number of hacks, but the new findings raises concerns that Russia's intrusions have been more extensive than originally thought. 

'While our analysis continues, we currently have no information that indicates that the power grid was penetrated in this cyber incident,' said Todd Breasseale, Department of Homeland Security Assistant Secretary for Public Affairs.

Monday's revelation about new cases of attempted or potentially successful cyber intrusions came just days after the US expelled 35 Russian intelligence operatives.

The 'spies' were stationed in the Russian embassy in Washington and the Russian consulate in San Francisco and belong to the intelligence agencies the FSB and the GRU.

The White House claims Democratic National Committee and the emails of a key Hillary Clinton adviser were hacked the Kremlin. 

In a statement outgoing president Obama said: 'In addition to holding Russia accountable for what it has done, the United States and friends and allies around the world must work together to oppose Russia's efforts to undermine established international norms of behaviour, and interfere with democratic governance.'