Story highlights Sen. Richard Burr, a North Carolina Republican, leads the Senate intelligence committee

The Senate intelligence panel has also invited Facebook, Twitter and Google to testify

(CNN) Senate Intelligence Committee Chairman Richard Burr said Wednesday that the panel "has more work to do" to determine whether there was collusion between Russian officials and Donald Trump's team during last year's presidential election.

"The committee continues to look into all evidence to see if there was any hint of collusion," Burr said at a Capitol Hill news conference, standing alongside the committee's top Democrat, Mark Warner of Virginia.

Burr said the committee continues to look for "any hint of collusion" but has not come to any initial conclusions on that question, as it is still conducting interviews and reviewing documents, including 25 additional interviews this month.

The news conference Burr and Warner held to provide a progress report on their monthslong probe underscored their investigation is growing in scope and is not shying away from the question of collusion — which Trump has repeatedly dismissed as a "hoax."

Burr and Warner said they have largely confirmed the conclusions the intelligence community reached under the Obama administration that the Russian government meddled in the 2016 US election.

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