WASHINGTON — The House Intelligence Committee’s investigation into Russian interference in the presidential election is “off the rails” and its credibility is in doubt, according to the top Democrat on the committee.

Rep. Adam Schiff (D-Calif.) accused the top committee Republican, Rep. Devin Nunes (R-Calif.) of damaging the “integrity” of their investigation by canceling a public hearing with high-profile witnesses and running President Trump with new evidence without showing the committee.

“We are all quite in the dark on this,” fumed Schiff on CBS’s “Face the Nation.”

“We, I think, suffered really two serious blows to the integrity of the investigation this week, one, with that unilateral trip to the White House, but the other with a cancellation of an open hearing.”

On Monday the FBI Director James Comey announced to the committee the FBI is investigating the Trump campaign’s links to Russia and shot down President Trump’s claims former President Obama wiretapped him.

Nunes helped to change the narrative Wednesday by heading to the White House and announcing that communications by Trump associates were “incidentally” picked up intelligence surveillance.

Nunes didn’t tell the rest of the committee about his findings.

Rep. Trey Gowdy (R-SC) said he still hasn’t seen Nunes’ evidence and but believes it was “unrelated” to the committee’s Russia investigation.

“He has not shown it to me,” Gowdy told CBS’s “Face the Nation.”

“My understanding is Chairman Nunes briefed the commander-in-chief on matters unrelated to the Russia investigation. So if that’s a big deal in Washington, then we’ve sunk to a new low.”

Asked about health of the committee’s ability to continue to investigate, Gowdy said: “I think it’s fine.”

Nunes and Schiff once had joint press conferences on their bipartisan investigation, but they’ve split to feuding factions.

By Friday, Nunes made a solo announcement he’s canceling Tuesday’s high-profile public hearing with former Director of National Intelligence James Clapper, former CIA Director

John Brennan and former acting Attorney General Sally Yates.

Schiff held a separate press conference where he blamed Nunes for trying to “choke off” public information. Nunes said they’d instead hold a private hearing with Comey on unresolved questions within a classified setting.

“The country really needs to have an independent, credible investigation in the House,” Schiff said Sunday. “…Where I think that the House process went off the rails was with that venture by the chairman to the White House.”

The breakdown has increased Democrats’ calls for an independent commission to investigate Russia’s interference in the 2016 presidential election.

Meanwhile, across the Capitol, the Senate intelligence committee will continue with its Russian probe. The committee’s top Democrat, Sen. Mark Warner (D-Va.) is “open” to an independent panel but said he still has “trust” his GOP chairman, Sen. Richard Burr (R-NC) can lead a bipartisan investigation.

“This is the most important thing that I’ve ever done in my public life,” Warner told NBC News’ “Meet the Press.”

Former Trump advisor Roger Stone and former campaign chairman Paul Manafort have both volunteered to testify before Congress in hopes to clear their names.

Stone was in contact with the hacker into the Democratic emails that were exposed on Wikileaks, known as Guccifer 2.0. The US intelligence believes the hacker was a Russian agent, which Stone refutes.

“I have had no contacts or collusions with the Russians,” Stone told ABC’s “This Week.”