Roger Stone, a one-time campaign and political adviser to now-President Trump, has told the House Intelligence Committee he is willing to testify on the ongoing investigation into Russia's influence in the 2016 election, according to his attorney.

Carter Page, a foreign policy adviser to Trump during the campaign, is also willing to testify, according to CNN.

That now makes three former Trump aides agreeing to testify voluntarily to the House Intelligence Committee, as earlier today Committee Chairman Devin Nunes announced that Trump's former campaign adviser Paul Manafort would testify.

Stone, Manafort and Page have long been the lynchpins to theories that have sought to conclusively link the Trump campaign to Russia.

A letter from Stone's attorney to the committee says, "Mr. Stone deeply resents that several members of your Permanent Select Committee have intimated that he has committed treason in his political, press and social media activities," and so is "eager to voluntarily appear in open session" to address the claims.

Earlier Friday, Nunes announced the committee wanted closed-door testimony from FBI Director James Comey and NSA Director Admiral Mike Rogers this Tuesday, and that the meeting would supplant the already-scheduled second open hearing. But Democrats seized on the cancellation of the open meeting, claiming that it was an attempt by the White House to keep the public in the dark on the Russia investigation.

Meanwhile, Democrats, including House Minoritly Leader Nancy Pelosi and Democratic House Whip Steny Hoyer continue to call for independent committee or commission to investigate the matter. On the Republican side, Senator John McCain has also called for an independent investigation.