Pelosi's letter was sparked by claims Wednesday night that Nunes, R-Calif., allegedly sent the White House an altered version of a still-classified controversial memo that purportedly reveals possibly misleading actions by both the FBI and the Justice Department in order to obtain a warrant to surveil a former Trump campaign adviser in October 2016 as part of their probe of Russian interference in the 2016 presidential election.

House Democratic Leader Nancy Pelosi wrote Speaker Paul Ryan on Thursday demanding the removal of Rep. Devin Nunes as Intelligence Committee chairman, saying he has "disgraced" the committee with "dishonest" actions related to an ongoing probe of Russia and the Trump presidential election campaign.

The Intelligence Committee had voted to send the White House a different version of that memo for review and potential release.

"It is long overdue that you, as Speaker, put an end to this charade and hold Congressman Nunes and all Congressional Republicans accountable to the oath they have taken to support and defend the Constitution, and protect the American people," Pelosi, D-Calif., wrote Ryan, R-Wisc.

"The integrity of the House is at stake," she wrote.

Rep. Adam Schiff of California, the ranking Democrat on the Intelligence Committee, has called the memo that Nunes wants to release little more than a "conspiracy theory."

The memo, according to Schiff, suggests that "a cabal of senior officials within the FBI and the Justice Department were so tainted by bias against President Trump that they irredeemably poisoned the investigation."

Read Pelosi's full letter to Ryan below: