Russia hacking claims: 'No evidence' Republicans seriously affected
The head of the FBI has said the bureau has no evidence that Russia successfully hacked US President-elect Donald Trump's White House campaign.
James Comey said some local Republican campaign systems were hacked, but damage was limited compared to the attack on their Democrat rivals.
Intelligence chiefs blame Moscow for the hacking of Democratic Party emails, aimed at damaging Hillary Clinton.
Russia has described the allegations as a witch-hunt.
Mr Trump accepted a report into the hacking released by intelligence chiefs on Friday but declined to single out Russia as being behind the hacks.
He has accused Democrats of being "careless" for allowing the leak.
Meanwhile CNN quoted unnamed US officials as saying that during a meeting with the intelligence chiefs last month Mr Trump was given documents that included allegations of compromising material about the president-elect held by Russian agents.
The FBI was investigating the accuracy and credibility of the allegations, the network said.
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Testifying before the Senate Intelligence Committee, Mr Comey said state and local Republican campaigns were broken into, as well as some email domains formerly used by the Republican National Committee (RNC).
But "we do not have any evidence that the Trump campaign or the current RNC systems were hacked," he said.
Meanwhile Director of National Intelligence James Clapper told the committee that the hacking report was based on a combination of human sources, technical data and open-source information.
An unclassified version of the report has been published but Gen Clapper said much of it was classified to protect sensitive sources and methods.
Russian agents are alleged to have sent stolen Democratic emails to WikiLeaks to try to swing the vote for Mr Trump.
Russia has denied any involvement in the hacking and WikiLeaks founder Julian Assange says Moscow was not the source for the site's mass leak of emails from the Democratic Party.
According to CNN, the Washington Post and NBC News, citing intelligence sources, agencies had intercepted communications following the election which showed senior Russian government officials celebrated Donald Trump's win over rival Hillary Clinton.