WASHINGTON >> The chairman of the House committee investigating Russian meddling in last year’s presidential election admitted today that secret documents that he said forced him last week to rush to brief President Donald Trump came from inside the White House.

The admission prompted three Democrats on the committee to call for Rep. Devin Nunes, R-Calif., to recuse himself from the investigation, including Rep. Adam Schiff of California, the senior Democrat on the committee.

“After much consideration, and in light of the chairman’s admission that he met with his source of information at the White House, I believe that the chairman should recuse himself from any further involvement in the Russia investigation, as well as any involvement in oversight of matters pertaining to any incidental collection of the Trump transition, as he was also a key member of the transition team,” Schiff said in a statement. “This is not a recommendation I make lightly, as the chairman and I have worked together well for several years.”

Rep. Eric Swalwell, D-Calif., said in a statement: “Chairman Nunes should no longer be anywhere near this investigation, let alone leading it.”

A third Democrat on the committee, Rep. Jackie Speier of California, also called for Nunes to step down. “My fears have been validated,” she said in a statement. “Through his bizarre and partisan actions over the last week, Chairman Nunes has demonstrated to the entire nation why he is unfit to lead our critical investigation into ties between President Trump’s administration and Moscow.”

Democrats on the committee have been hesitant previously to demand that Nunes withdraw from the investigation. But two developments in recent days, including Nunes’ cancellation of the committee’s second public hearing that was scheduled for Tuesday, have raised tensions on the committee.

Last week, Nunes angered Schiff and other Democrats on the committee by revealing that he had seen secret documents that he said showed that some members of the Trump transition team had turned up in legally authorized intercepts of foreign officials. The documents, Nunes said, had nothing to do with the Russia investigation. But he revealed them to reporters and then discussed them with Trump without sharing them with the committee.

It was only Monday that Nunes acknowledged that he had gone to the White House compound to view the documents.

“The information comprised executive branch documents that have not been provided to Congress,” his committee staff said in a prepared statement. “Because of classification rules, the source could not simply put the documents in a backpack and walk them over to the House Intelligence Committee space. The White House grounds was the best location to safeguard the proper chain of custody and classification of these documents, so the chairman could view them in a legal way.”

Another Democrat, Rep. Henry Cuellar of Texas, said the developments proved the need for an indepedndent commission to investigate Russian meddling and whether Trump campaign officials colluded with Russia in the effort.

“We already know Russia hacked President Trump’s opponents to help him with the election,” Ceullar said. “We know senior officials close to the president had personal and financial dealings with Russian government officials, including intelligence agents. New revelations emerge almost weekly. What do we still not know?”

There were signals that some Republicans also were becoming concerned about the congressional investigations of Russian meddling. Former Vice President Dick Cheney said in an interview with “Business Insider” that it was important to take the Russian meddling allegations very seriously.

“There’s no question that there was a very serious effort made by (Russian President Vladimir) Putin and his government, his organization, to interfere in major ways with our basic fundamental democratic processes,” he said. “In some quarters, that could be considered an act of war.”

White House press secretary Sean Spicer declined today to provide a White House version of events, saying “all of what I know has been available through public comments.”

“He is the one who has discussed what he is reviewing,” Spicer said, referring to Nunes. “And so I will leave it up to him and not try to get in the middle of that.”