According to Comey, the FBI began their investigation in late July. Several top lawmakers have also said they've seen no evidence of Trump's unsubstantiated claims.
The response amounted to Trump's first direct public response to Comey's testimony, in which he also confirmed the Department of Justice was looking into potential ties between the Trump campaign and Russian government. But Comey said the intense public interest in the matter - and permission from the Justice Department - made it appropriate to do so. Majority Republicans concentrated their questions on leaks of classified information - a concern that Trump frequently mentions - and media reports on issues such as contacts between former Trump national security adviser Michael Flynn and Russian officials. "I can't go into those details here".
"I know speculating is part of human nature, but it really isn't fair to draw conclusions simply because I say that I can't comment", Comey said. "But it is the way it has to be".
Under questioning from the committee's top Democrat, Rep. Adam Schiff, the Federal Bureau of Investigation director also publicly contradicted a series of tweets from Trump that declared the Republican candidate's phones had been ordered tapped by President Barack Obama during the campaign.
TRUMP tweet: "FBI Director Comey refuses to deny he briefed President Obama on calls made by Michael Flynn to Russian Federation".
"It certainly wasn't our intention to say that today, because we don't have any information on that subject", Comey said.
"No individual in the United States can direct electronic surveillance of anyone", he continued.
Rogers later said that he had "seen nothing from the NSA side that we engaged in any such activity".
In a statement, Clapper said he did not know about any evidence gathered after January 20 and Coons, citing circumstantial evidence to support allegations of collusion, advised Press Secretary Sean Spicer that he "would do well to quote me accurately and fully in the future". Then, he poured cold water on the startling claim about Barack Obama that Mr Trump has failed to provide any evidence to support. "That includes any links between the Trump campaign".
He said that the United States should be prepared for Russian Federation to attempt to intervene in the 2018 midterm elections or the 2020 presidential election.
"They'll be back in 2020, they may be back in 2018". The probe is reportedly part of a broader investigation of Russian interference in last year's presidential election. "One of the lessons they may draw from this is that they were successful because they introduced chaos and division and discord and sewed doubt about the nature of this unbelievable country of ours and our democratic process", Comey explained.
"But it is also possible, maybe more than possible, that they are not coincidental, not disconnected and not unrelated, and that the Russians used the same techniques to corrupt USA persons that they have employed in Europe and elsewhere".
According to Stewart, the intelligence community agreed with him that Russian Federation wanted to disrupt the election but didn't favor one candidate or the other up until Obama asked for an investigation in December. In fact, Comey said during the hearing that Putin clearly wanted Clinton to lose. He suggested the Russians were trying to undermine a Clinton presidency, not get Trump elected.
The report said the Russian campaign aimed to use computer hacks, leaks, and other methods to undermine faith in the US electoral system and denigrate Democratic candidate Hillary Clinton.
The committee's chairman, Republican Devin Nunes, opened the hearing by denying a claim from President Trump that there had been a wiretap on his Trump Tower in NY.
"We know there was not a physical wiretap of Trump Tower".