Story highlights The assessment of Russia's role was "by the entire intelligence community," says John Kirby

The State Department Spokesman says the information is "rock solid"

Donald Trump has said "it is very hard to determine who was doing the hacking"

(CNN) The US administration is "is 100% certain in the role that Russia played" in election-related hacking, State Department Spokesman John Kirby told CNN.

"There's no question" about what Russia did to "sow doubt and confusion, and getting involved through the cyber domain, into our electoral process," he told Christiane Amanpour on Tuesday.

"And that's not just an assessment by the President or by Secretary Kerry or other Cabinet officials. It's an assessment by the entire intelligence community," he added.

President-elect Donald Trump has raised doubts about that assessment and suggested he has inside information about who was involved.

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