WASHINGTON—A Republican memo released Friday by the House of Representatives alleges abuses in how top law-enforcement officials sought the surveillance of a onetime adviser to Donald Trump, suggesting partisan motives are behind the investigation of ties between the president’s associates and Russia.

The release marked the culmination of tensions this past week between congressional Republicans and the White House on one side, and Democrats and leaders in the Trump administration’s own Justice Department on the other. Top Federal Bureau of Investigation officials had publicly objected to the memo’s release, saying they had “grave concerns” about factual omissions and accuracy.

Mr. Trump, who had to sign off on the memo’s release, has been at odds for much of the past year with several Justice Department leaders having to do with the Russia probe. He fired FBI Director James Comey and publicly criticized his own appointees, including Attorney General Jeff Sessions, over his recusal from the Russia matter, and Deputy Attorney General Rod Rosenstein, who now oversees the investigation by special counsel Robert Mueller.

The four-page memo, written by the GOP staff of the House Intelligence Committee, also criticizes the Justice Department and FBI, suggesting partisan bias in the handling of surveillance against former Trump aide Carter Page, which was approved by a secret federal court in the fall of 2016. The memo says research compiled by Christopher Steele, a former British intelligence official who was conducting opposition research on Mr. Trump that was then being funded by Democratic-linked groups, was the driving force in the government’s surveillance applications on Mr. Page.

The memo contends that by not stating the partisan origin of the research, prosecutors obscured a possible political motive for the surveillance of Mr. Page, marking a “troubling breakdown of legal processes.” But the document’s claims are difficult to evaluate without access to the underlying, highly classified law-enforcement material that it was based on. It also doesn’t address or dispute the research collected by Mr. Steele that was included in the warrant application, and it recommends no changes to U.S. intelligence programs.

The importance of the Steele dossier to the surveillance applications and the disclosures by the FBI are a matter of intense disagreement. A person who has reviewed the surveillance-warrant application said Mr. Steele’s research formed only a part of the application. The other information included in the application hasn’t been declassified, though Mr. Trump has that authority.

Rep. Adam Schiff, the top Democrat on the intelligence committee, disputed the memo’s contention that the FBI didn’t disclose the political motive behind Mr. Steele’s research, saying that the memo is a political document full of omissions and cherry-picked facts designed to muddy the waters of the Russia investigation, which has already ensnared several top Trump advisers. Mr. Mueller has also asked to interview the president as he investigates whether Mr. Trump obstructed justice, which the president has denied.

“This was about telling a political story that’s helpful to the president. It’s about telling a political story that’s designed to injure the work of the special counsel and to discredit it,” said Mr. Schiff.

Democrats on the committee have compiled their own memo on the matter, which addresses the information that prosecutors used beyond Mr. Steele’s research, but the GOP-controlled committee has so far blocked its release.

Mr. Page has been on the radar of U.S. intelligence since 2013, when Russian spies made an attempt to recruit him. He hasn’t been accused of any wrongdoing and has called the investigation baseless. He left Mr. Trump’s campaign in September 2016 after reports that a July 2016 trip he took to Moscow was of interest to investigators.

Law-enforcement officials obtained an initial warrant against Mr. Page in October 2016, then three renewals, according to the memo. If there was no lapse in surveillance, that would mean that Mr. Page was the subject of a surveillance as recently as October 2017. Such surveillance applications, and each renewal, must be approved by the U.S. Foreign Intelligence Surveillance Court.


The memo describes the process by which the government got a secret warrant under the law that governs the secret court, the Foreign Intelligence Surveillance Act, for Mr. Page. The process, which is supervised closely by senior U.S. officials and a federal judge, required several layers of approval from top FBI and Justice Department officials.

At least two of those renewals occurred while Mr. Trump was president and at least one was authorized by a Justice Department official he appointed. A person familiar with the matter said that four separate federal judges approved the surveillance of Mr. Page, and all of those judges were appointed by Republican presidents.

The memo is critical of Mr. Steele and notes that prosecutors in their application for the warrant didn’t explicitly state that he was working for a firm funded by Democrats. But the FISA application did disclose Mr. Steele was being paid by a law firm working for a major political party, according to a person familiar with the matter. Redacting the names of U.S. people or organizations who aren’t the subject of an investigation is a common practice in government legal filings, designed to protect privacy.

The bureau considered Mr. Steele a reliable source from previous investigations, having helped provide information during a federal probe into alleged corruption at FIFA, the world soccer organization, according to a person familiar with the arrangement. The memo says he was terminated as an FBI source after contacts with the media in October 2016—and that he didn’t properly disclose to the bureau that he had also spoken to reporters in September. Representatives for Mr. Steele didn’t respond to a request for comment.

Much of the information in the memo had been previously reported. One new element related to purported testimony of Andrew McCabe, a deputy FBI director who just stepped down this past week, about the importance of the Steele dossier in obtaining surveillance warrants on Mr. Page. The memo alleges that Mr. McCabe testified before the House Intelligence Committee in December that “no surveillance warrant would have been sought…without the Steele dossier information.”

Officials in Congress and the Justice Department familiar with Mr. McCabe’s testimony said the memo mischaracterized what he told lawmakers. He was asked what percentage of information in the FISA application was provided by Mr. Steele, and he demurred, saying the FBI didn’t evaluate such applications in such a way. Mr. McCabe was asked if it might have accounted for half of the warrant application, and he said he didn’t know, one person familiar with the matter said.

Mr. Trump and other Republicans cheered the buildup to the document’s release, fueled by social-media campaigns, saying it would expose law-enforcement wrongdoing in prosecuting the president. Mr. Trump himself earlier Friday accused senior officials and investigators at the FBI of being biased against Republicans and favoring Democrats, dovetailing with a theme of the memo.

In a statement after the memo’s release, the White House said it “raises serious concerns about the integrity of decisions” of senior officials.

In a brief statement, Mr. Sessions said, in part, “I have great confidence in the men and women” of the Justice Department. FBI Director Christopher Wray said in a video message to staff: “I stand by our shared determination to do our work independently and by the book.”

“We stay laser-focused on doing great work even when it’s not easy—because we believe in the FBI,” Mr. Wray said.

One person close to Mr. Trump said this week that the president believes the memo undermines the credibility of Mr. Rosenstein, who is named in the document as having approved an application to continue surveillance of Mr. Page, in the spring of 2017.

Asked Friday if he had confidence in Mr. Rosenstein, Mr. Trump said: “You figure that one out.”

Mr. Rosenstein supervises the special-counsel investigation being led by Mr. Mueller, after Mr. Sessions recused himself. Mr. Trump has frequently expressed displeasure about the investigation. Mr. Rosenstein’s dismissal would give Mr. Trump the chance to name a new deputy attorney general who would oversee that probe.

One senior White House official said there was “zero chance” that Mr. Trump would fire Mr. Rosenstein over the memo. The official described Mr. Trump’s refusal to publicly express confidence in Mr. Rosenstein as a mix of his frustration with the investigation and pleasure derived from teasing the media.Justice Department officials also didn’t expect Mr. Rosenstein to be fired and weren’t preparing for that possibility, saying that Mr. Sessions remains in his job even as Mr. Trump has publicly mused about his firing since last summer.

The president has denied having worked with Russia to influence the election, although several people in Mr. Trump’s orbit have admitted to having had contact with Russians during the campaign. Moscow has denied election meddling.

The memo is drawn from highly classified Justice Department and FBI documents. A handful of top staff and members of Congress won access to those records in early January, over the objection to Justice officials who appealed directly to House Speaker Paul Ryan that they were too sensitive to be shared with the legislature.

—Michael C. Bender, Aruna Viswanatha and Del Quentin Wilber contributed to this article.