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Pressure continued to mount on Tuesday for House Intelligence Committee Chairman Devin Nunes to recuse himself from the panel’s investigation into Russia amid a growing firestorm of criticism for meeting with a confidential source at the White House to review intelligence reports.

The California Republican told reporters "the investigation continues" and questioned why he would remove himself from the probe despite growing concerns about his impartiality after sharing information about the investigation with President Donald Trump before members of the committee.

“I’d like to know first what the purpose of that would be. Because someone asks?” he responded to a CNN reporter’s question about stepping down. “I mean, that’s not how decisions are made.”

Rep. Adam Schiff, the highest ranking Democrat on the Intelligence Committee, on Monday called for Nunes to step down after the Republican acknowledged he went to the White House the day before he claimed communications from Trump and his advisers may have been “incidentally” collected by U.S. intelligence agencies.

"I believe the public cannot have the necessary confidence that matters involving the President's campaign or transition team can be objectively investigated or overseen by the chairman," Schiff said.

House Speaker Paul Ryan briskly dismissed the calls for Nunes to step down from the Russia inquiry at a press conference Tuesday. Ryan also said he did not know the identity of the secret source Nunes met with at the White House.

Rep. Walter Jones, R-N.C., became the first Republican to call on Nunes to recuse himself late Tuesday, though he does not sit on the intelligence committee.

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Democrats frustration with Nunes only intensified on Tuesday after the chair abruptly cancelled the rest of the committee’s meetings this week. Democratic Rep. Jim Himes said on MSNBC’s “Morning Joe” that an intelligence committee meeting Monday was canceled, as well as an open hearing set for Wednesday and an unrelated meeting Thursday.

“Not only has this investigation sort of had a shadow cast on it, but the committee's been put into suspended animation,” Himes said.

On Monday, Nunes' spokesman confirmed that the chairman met with a source at the White House grounds to look at reports. He's now under criticism for failing to tell the top Democrat on the intelligence committee about his White House visit, which Trump used to vindicate his claim that President Barack Obama had ordered surveillance on Trump Tower.

"We never talk about sources and methods," Nunes told NBC News when asked if he would reveal his source to fellow members of his committee.

Related: What Does It Mean That Trump May Have Been 'Incidentally' Surveilled?

White House spokesman Sean Spicer refused to comment Monday when asked why Nunes was on White House grounds.

Congress is investigating Trump's unverified claim earlier this month that Trump's campaign headquarters was wiretapped and a larger probe into whether Russia interfered in the presidential election and may have colluded with members of the Trump campaign.

Nunes' visit to the White House has clouded the already complicated inquiry.

Sen. Lindsey Graham said Tuesday on TODAY that Nunes at the very least has "put his objectivity in question" and "lost his ability to lead."

"He’s gone off on a lark by himself, a sort of Inspector Clouseau investigation here," Graham said, referring to the bumbling detective of "The Pink Panther" series.

Related: Schiff Calls on GOP Intel Chair Nunes to Recuse Himself From Russia Probe

Rep. Eric Swalwell, a Democratic member of the House Intelligence Committee, said on "Morning Joe" that Nunes has compromised the investigation by not properly sharing information.

"It's time for Devin Nunes to leave this investigation, let alone lead it. He should be gone," Swalwell said, adding, "This is what a cover-up to a crime looks like, we're watching it play out right now."