By Steve Holland and Warren Strobel

WASHINGTON (Reuters) – A secret Republican memo alleging FBI bias against President Donald Trump likely will be released on Thursday, a Trump administration official said, a move that would put the White House in direct confrontation with the top U.S. law enforcement agency.

The Federal Bureau of Investigation issued a rare rebuke on Wednesday to the president and his fellow Republicans in Congress who are pushing to release the four-page document crafted by Republican members of the House of Representatives Intelligence Committee.

“The FBI was provided a limited opportunity to review this memo the day before the committee voted to release it,” the FBI said in a statement. “As expressed during our initial review, we have grave concerns about material omissions of fact that fundamentally impact the memo’s accuracy.”

Justice Department officials have also said releasing the memo could jeopardize classified information.

The administration official, who spoke on condition of anonymity on Wednesday night, did not elaborate on the expected release.

The fight over the memo reflects a wider battle over Special Counsel Robert Mueller’s criminal probe into potential collusion between the Trump campaign and Russia to help him win the 2016 presidential election. Russia and Trump have both denied the allegations. Mueller’s investigation and the FBI probe that preceded it have hung over Trump’s year-old presidency.

Democrats say the four-page memo is misleading, based on a selective use of highly classified data and intended to discredit Mueller’s investigation.

Representative Devin Nunes, the intelligence committee’s Republican chairman who commissioned the document, dismissed the objections to its release as “spurious.”

In a bid to block its release, Representative Adam Schiff, the intelligence committee’s top Democrat, said late on Wednesday he had discovered that Nunes had sent the White House a version of the memo that was “materially altered” and not what the committee voted to release on Monday. It was not clear if the panel’s Republicans would hold a new vote on the altered document.

The memo accuses the FBI and Justice Department of misleading a Foreign Intelligence Surveillance Court judge in March as they sought to extend an eavesdropping warrant against Trump campaign adviser Carter Page, four sources familiar with it have said.

They said memo contends that the FBI and Justice Department failed to tell the judge that some of the information used to justify the warrant included portions of a dossier of Trump-Russia contacts that was opposition research paid for by Democrats.

However, the sources said the memo does not mention that the request to extend surveillance on Page, which began before Trump took office, also relied on other highly classified information and that U.S. agencies had confirmed excerpts from the dossier included in the request.

U.S. intelligence agencies have concluded that Russia interfered in the 2016 campaign using hacking and propaganda to attempt to tilt the race in favor of Trump. The president has called Mueller’s investigation a “witch hunt” and “hoax.”

(Reporting by Steve Holland, Warren Strobel, Jonathan Landay; Writing by Doina Chiacu; Editing by Will Dunham)