Sens. Richard Burr and Mark Warner. CNN The chairman and the vice chairman of the Senate Intelligence Committee, Richard Burr and Mark Warner, told reporters on Wednesday that the committee had concluded, for now, that it trusts the intelligence community's assessment, published in January, outlining why and how Russia interfered in the 2016 US election.

In a wide-ranging press conference on the status of the committee's investigation into Russian meddling, the senators also said the committee was continuing to look into whether President Donald Trump's campaign colluded with Russian officials.

The declassified version of the intelligence community's report said "Russia's goals" in meddling in the election "were to undermine public faith in the US democratic process, denigrate" Democratic nominee Hillary Clinton, and "harm her electability and potential presidency."

The report also said Russia aimed to help Trump win the election.

Burr said the committee had interviewed every official who had a hand in writing the assessment, adding that staff and lawmakers spent "nine times as long" reviewing the report as the officials spent writing it.

Over the past eight months, Burr said, the committee has conducted over 100 interviews that yielded nearly 4,000 pages of transcripts. It has also reviewed almost 100,000 pages of documents, ranging from highly classified intelligence to emails and cyber analysis, he said.

The committee has also interviewed every relevant official from the Obama administration about President Barack Obama's response to Russia's election interference, Burr said.

"The issue of collusion" between the Trump campaign and Russia "is still open," he said. He did not elaborate, except to say that the committee had not come to any conclusions and that the investigation is ongoing.

Burr said the committee had examined some of the most controversial moments of the election, including an event at the Mayflower Hotel in Washington, DC, last year to celebrate Trump's first major foreign-policy speech as a candidate. The Russian ambassador to the US, Sergey Kislyak, attended the event and spoke with high-level campaign officials like Jeff Sessions, now the attorney general, and Jared Kushner, Trump's son-in-law who's now a top White House adviser.

The committee interviewed seven people present at the event, and their testimony was consistent, Burr said. But investigators will continue to examine the event as additional information becomes available.

The committee also interviewed "every person involved" in what many perceived as a weakening of the GOP's campaign platform on Russia and Ukraine. Burr said the committee was still looking into the platform change.

Regarding the memos that James Comey, the former FBI director, wrote about Trump's attempts to end the investigation into his former national security adviser, Michael Flynn, Burr said "the committee is satisfied that this issue has reached a logical end" as it related to the committee's Russia investigation.

Congressional investigators are also examining how Russia used Facebook, Twitter, and Google to target political ads and spread misinformation during the election. The tech giants came under intense pressure to disclose everything they knew about how foreign actors had exploited their platforms after Facebook said last month that 470 "inauthentic accounts" linked to Russia had purchased political ads between 2015 and 2016.

Warner said he believed it was "important for the public to see" the ads purchased by the Russia-linked accounts, adding that the use of political advertising on social media "may double or triple again in the next election cycle."

"I was concerned at first that some of these companies did not take this threat seriously enough," Warner said. "But I believe they're recognizing that threat now, and they are providing us with information."

Burr said the committee had "hit a wall" regarding the verification of the collection of memos about Trump and Russia written by Christopher Steele, a former British spy. He said the committee's inquiries and requests for an interview with Steele had "gone unaccepted."

It is unclear whether Steele is cooperating with Robert Mueller, the FBI's special counsel who is conducting a parallel investigation into Russia's election interference. A similar probe by the House Intelligence Committee is ongoing.

Burr said the committee had been "incredibly enlightened" at its "ability to work backwards" from the dossier between November 2016 until June 2016. But "getting past that point has been somewhat impossible," Burr said.