In the latest twist in the controversy over President Donald Trump’s alleged ties to Russia, the head of the congressional committee investigating the matter has recused himself. Congressman Devin Nunes, who chairs the House Intelligence Committee, removed himself temporarily from his committee's investigation following accusations of ethics violations.

“Several left-wing activist groups have filed accusations against me with the Office of Congressional Ethics,” Mr Nunes said in a statement on Thursday morning. “The charges are entirely false and politically motivated, and are being levelled 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.”

The criticism stemmed from Mr Nunes' decision to bring sensitive intelligence to Mr Trump before consulting with his committee. Two weeks ago, Mr Nunes announced he had discovered evidence of “incidental surveillance” of the Trump transition team – and possibly Mr Trump himself – leading up to the inauguration.

The information initially seemed to support Mr Trump's unsubstantiated claim that former President Barack Obama had wiretapped his offices. Mr Trump told reporters he felt “somewhat” vindicated by the discovery.

However, Mr Nunes later clarified that the surveillance appeared to be both “legal” and “normal”. Still, he chose to bypass his committee and bring the information directly to the White House. He later apologised for the hasty response.

“It was a judgement call on my part,” he told reporters on 23 March. “Sometimes you make the right decision, sometimes you make wrong decision.”

High-ranking Democrats called for Mr Nunes to recuse himself from the Russia probe, saying he had compromised the integrity of the investigation.

“What he did was basically to go to the president, who is being investigated by the FBI and others and by the intelligence committee, to give them information,” Representative Elijah Cummings, the ranking member of the House Oversight Committee, told CNN. “Basically what he has done is he has scuttled and put a cloud over his own investigation.”

Mr Nunes has previously refused to step down from the House investigation. On Thursday morning, however, the bipartisan House Ethics Committee announced their own investigation of Mr Nunes, based on reports that he “may have made unauthorised disclosures of classified information” during his press conference.

Mr Nunes called the allegations “baseless”, but agreed to remove himself temporarily from the House investigation.

House Speaker Paul Ryan said he supported Mr Nunes’s decision and said the Congressman was eager to talk to the ethics panel.

"It is clear that this process would be a distraction for the House Intelligence Committee's investigation into Russian interference in our election," Mr Ryan said.

Representative Mike Conaway will take over the investigation, assisted by Representatives Trey Gowdy and Tom Rooney. Mr Ryan said he was confident that Conaway “will oversee a professional investigation into Russia's actions and follow the facts wherever they lead”.

Representative Adam Schiff, the ranking Democrat on the Intelligence Committee, said he was unaware of Mr Nunes decision to step down before the public announcement. Still, he commended Mr Nunes for making what he called "a very difficult decision," and said he looked forward to continuing the committee's work with Mr Conaway.