Rep. Devin Nunes, chairman of the House Intelligence Committee. Drew Angerer/Getty Images

Rep. Devin Nunes, the head of the House Intelligence Committee, announced Thursday morning that he would step aside from the committee's investigation into Russian meddling in the 2016 presidential election.

Nunes' announcement came as the House Ethics Committee said it was investigating whether he had disclosed classified information without authorization.

Nunes blamed the move on "left-wing activist groups" that filed complaints with the Office of Congressional Ethics. He maintained that accusations of bias were "entirely false and politically motivated," but said he chose to temporarily step away.

"Several left-wing activist groups have filed accusations against me with the Office of Congressional Ethics," Nunes said in the statement. "The charges are entirely false and politically motivated and are being leveled just as the American people are beginning to learn the truth about the improper unmasking of the identities of US citizens and other abuses of power.

"Despite the baselessness of the charges, I believe it is in the best interests of the House Intelligence Committee and the Congress for me to have Representative Mike Conaway, with assistance from Representatives Trey Gowdy and Tom Rooney, temporarily take charge of the committee's Russia investigation while the House Ethics Committee looks into this matter."

Nunes told The Washington Post's Robert Costa he planned to return to the Russia investigation eventually. Nunes said he chose to step aside now because he was "facing ethics complaints about how he has handled classified information," according to Costa.

Nunes has come under fire in recent weeks for communications with the White House that critics have said are inappropriate in light of the committee's investigation into whether President Donald Trump's associates colluded with Russia to influence the outcome of the election.

Last month, Nunes bypassed committee members to visit the White House and brief Trump on classified intelligence reports that he said showed that members of Trump's transition team were swept up in incidental surveillance after the election.

Trump used that information to support his unsubstantiated claims made in early March that the Obama administration had wiretapped Trump Tower. Last week, however, reports surfaced that three White House officials had helped provide the intelligence documents to Nunes.

House Speaker Paul Ryan released a statement Thursday reaffirming his trust in Nunes and saying he supported his decision to recuse himself. Ryan said House Ethics Committee inquiries "would be a distraction for the House Intelligence Committee's investigation into Russian interference in our election."

The House Ethics Committee also released a statement Thursday saying it was investigating Nunes.

"The committee is aware of public allegations that Representative Devin Nunes may have made unauthorized disclosures of classified information, in violation of House Rules, law, regulations, or other standards of conduct," Rep. Susan Brooks, chairwoman of the committee, and Rep. Ted Deutch, the committee's ranking Democrat, said in the statement.

Brooks and Deutch said the committee was "investigating and gathering more information regarding these allegations." They also said that "the mere fact that it is investigating these allegations" did not "indicate that any violation has occurred or reflect any judgment on behalf of the committee."

Rep. Adam Schiff, the ranking Democrat on the House Intelligence Committee, said at a press conference Thursday that he supported Nunes' decision and looked forward to working with him on other issues facing the committee.

"I think it is in the best interest of the investigation," Schiff said. "It will, I think, allow us to have a fresh start moving forward."

A White House spokesperson said Thursday that "this is an internal matter for the House."

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