Burr said Wednesday that the panel is close to determining the assessment is accurate.
"You can not walk away from this and believe that Russian Federation is not now active in trying to create chaos in our election process", Burr said. Twitter officials have said they found about 200 accounts that seemed to be part of a Russian campaign to influence the 2016 presidential election, and cybersecurity firms have projected that number is higher. "We've got a tremendous amount of documents still to go through".
The chairman acknowledged the committee is still probing any possible collusion between Trump associates and the Russians, but wouldn't discuss anything learned so far.
The lawmakers said that though they have reached no conclusion about whether the campaign colluded with the Kremlin - the question also at the heart of a separate criminal investigation by special counsel Robert Mueller - their investigation has left no doubt about a multi-pronged Russian effort to meddle in American politics.
While both Burr and Vice Chairman Sen.
Burr and the committee's ranking Democrat, Mark Warner of Virginia, stressed that the Russian interference campaign has continued after the election. "The committee can not really decide the credibility of the dossier without understanding things like who paid for it, who are your sources and sub-sources", Burr added. "Who were your sources and subsources?"
"We need to be on guard", Vice Chairman Mark Warner, D-Va., added. That report said Russian Federation waged a cyber and disinformation campaign to discredit Hillary Clinton, help Donald Trump's campaign, and undermine faith in the democratic process.
"Now again, this is not something that we have closed, but we have exhausted every person we can talk to get information that is pertinent to us relative to the Russian Federation investigation", he told a room of reporters.
The Intelligence Committee also has "reached a logical end" to its pursuit of information about Trump's firing of FBI Director James Comey.
"We have not come to any determination on collusion or Russia's preferences".
In addition to interviewing members of the Trump and Clinton presidential campaigns, they have also interviewed "every official of the Obama administration to fully understand what they saw... and more importantly what they did and did not do and what drove those actions", Burr said. The first is for Trump's personal attorney, Michael Cohen, who had been scheduled for a private staff interview last month, but the committee postponed the appearance and invited him to a public session instead after Cohen provided a statement to the media denying any collusion with Russian officials.
Also questioned were senior executives of social media companies such as Facebook and Twitter, which displayed numerous Russian-supported advertisements that were meant to exacerbate divisions among voters on hot-button issues before the election.
Warner, the vice chair of the committee, told reporters that "at the end of the day it's important that the public see these ads".
Twitter's presentation "showed an enormous lack of understanding from the Twitter team of how serious this issue is, the threat it poses to democratic institutions and again begs many more questions than they offered", Warner said.