House Intelligence Committee Chairman Rep. Devin Nunes. Pablo Martinez Monsivais/AP House Intelligence Committee Chairman Devin Nunes has temporarily stepped aside from the committee's probe into Russia's interference in the US election and whether President Donald Trump's campaign was involved.

His announcement comes as he has become the subject of an ethics investigation.

Nunes has come under intense scrutiny after his decision last month to bypass the rest of his committee and brief Trump on classified executive-branch documents he said showed that members of Trump's transition team had been swept up in government surveillance.

Nunes repeatedly had said he did not intend to step aside, but there have been questions about his ability to lead an independent investigation. Reports have said he obtained the documents from White House officials, despite his claims to the contrary.

But in a statement on Thursday, Nunes said he would allow Rep. Mike Conaway to lead the investigation while he waited for the House Ethics Committee to look into complaints filed against him by what he said were "several left-wing activist groups."

Those groups, Democracy 21 and Citizens for Responsibility and Ethics in Washington, requested the Office of Congressional Ethics investigate whether Nunes "publicly revealed classified information in violation of Rule 23 Clause 13" when he told reporters last month that he had obtained information about "American intelligence monitoring foreign officials" who may have "incidentally picked up communications of Trump transition team members."

Rule 23 Clause 13 of the House rules says:

"Before a Member, Delegate, Resident Commissioner, officer, or employee of the House may have access to classified information, the following oath (or affirmation) shall be executed: 'I do solemnly swear (or affirm) that I will not disclose any classified information received in the course of my service with the House of Representatives, except as authorized by the House of Representatives or in accordance with its Rules.'"

Nunes acknowledged that the documents he had obtained, and on which he had briefed the press, were classified. But he insisted that he did not break any rules because he did not go into detail about the content of the intelligence reports.

The House Intelligence Committee's probe into Trump and Russia had all but stalled by the end of last month, with Nunes blaming Democrats — and vice versa — for the impasse.

But Nunes had refused to step aside even as the committee's top Democrat, Rep. Adam Schiff, said it would be difficult, if not impossible, to conduct a "credible investigation" as long as Nunes refused to share the information he had obtained with the rest of the committee.

About the investigation's credibility with Nunes at the helm, Schiff told CNN on March 29, "I'd love to get back on track, but I'm not willing to say something is legitimate if it's not."

On Thursday, Schiff told reporters that Nunes' recusal was "in the best interest of the investigation."

"It will, I think, allow us to have a fresh start," he said.