This ethics complaint is apparently what drove Devin Nunes to finally step aside from the Trump-Russia probe

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 team was involved. It comes as he has become the subject of an investigation himself.

Nunes has been the subject of intense scrutiny for weeks following his decision 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 said repeatedly that he had no intention of stepping aside, despite questions about Nunes' ability to lead an independent investigation as reports surfaced that he had obtained the documents from White House officials directly, despite his claims to the contrary.

But he said in a statement on Thursday that he will allow Rep. Mike Conaway to lead the investigation while he waits for the House Ethics Committee to "look into" the complaints filed against him by "several leftwing activist groups."

Those groups, Democracy 21 and CREW (Citizens for Responsibility and Ethics in Washington) requested that 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 Ethics handbook states that "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 was still refusing 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.

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

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

"I think it will allow us to have a fresh start," he added.