Comey did not comment on further details of the investigation.
Trump created a controversy in early March when he tweeted without giving evidence that former President Barack Obama's administration had wiretapped Trump Tower in ny. Trump, tweeting from his seldom used @POTUS account, wrote that the directors told Congress that "Russia did not influence the electoral process".
The National Security Agency director Michael Rogers also denied Trump's claims during the hearing.
James Comey, who is answering questions on possible Russian interference in Donald Trump's US Election victory, admitted Moscow would continue to back European nations pursuing their own Brexit movements.
Democratic focus: Democrats' lines of inquiry will be about Russian's possible collusion with "with the Trump political campaign and how do we prevent this from happening in the future". On his part, the NSA Chief Mike Rodgers debunked another claim by the new administration that the British had wiretapped Trump.
Because it's hard to say that the president is a lying-ass liar, House Intelligence Chairman Devin Nunes (R-Calif.) had to add Monday, "Let me be clear, we know there was not a wiretap on Trump Tower".
He said the committee heard "damning" evidence about what Russian Federation did and how Russian Federation did it, and that it was in part an "inside job" to help attack American democracy.
Comey was repeatedly questioned on partisan lines, with Democratic lawmakers bearing down on him about ties between Republican operatives and the Russians, in particular claims by Trump confidante Roger Stone that he was in contact with the Russian hacker Guccifer 2.0.
"Because it is an open, ongoing investigation and is classified, I can not say more about what we are doing and whose conduct we are examining", he added.
It will be interesting to see if anything new comes from today's hearing.
The House Intelligence Committee will hear from FBI Director James Comey on whether USA officials believe Russian Federation tried to bolster Trump's chances in the election and if there were any connections between Moscow and Trump's campaign aides.
"The Democrats made up and pushed the Russian story as an excuse for running a bad campaign", he said.
"I have no confirmation that supports those tweets, and we have looked carefully inside the FBI", Comey said. The latter is much more wide-ranging and would include everything from "fake news" and misinformation campaigns to hacking and leaked emails.
"So you have no intelligence that suggests, or evidence that suggests, any votes were changed", Nunes asks.
The thrust: The White House wants you to think that the Federal Bureau of Investigation might have been investigating Trump at Barack Obama's request, even though Comey explicitly told House members that this wasn't the case.
The high-stakes testimony in the House Intelligence Committee - the first public hearing into both controversies - came as Trump sought to steer the news focus by calling the Russian Federation issue, which has been a cloud over his victory, "fake news".