The memo is not an intelligence document and reflects information the committee has gathered, which Democrats, the FBI and Justice Department have criticized as incomplete and misleading.
Current and former law enforcement officials said a major concern inside the FBI is that the rules governing classified information will impede their ability to respond to the memo's accusations when it becomes public.
The president told reporters in the Oval Office, "I think it's a disgrace what's happening in our country. . . . A lot of people should be ashamed of themselves and much worse than that."
The FBI and the Justice Department had lobbied strenuously against the memo's release. In a statement Wednesday, the FBI had said it was "gravely concerned" that key facts were missing from the memo, which, it said, left an inaccurate impression of how the agency conducted surveillance under the authority of the Foreign Intelligence Surveillance Court.
Friday morning, the president tweeted in anticipation of the memo's release, saying: "The top Leadership and Investigators of the FBI and the Justice Department have politicised the sacred investigative process in favor of Democrats and against Republicans - something which would have been unthinkable just a short time ago.'' He added: "Rank & File are great people!"
California Rep. Adam Schiff, the top Democrat on the House Intelligence Committee, tweeted in response, "No, Mr. President it's worse than that. The country's top elected leader has agreed to selectively and misleadingly release classified info to attack the FBI - that's what would have been unthinkable a short time ago."
The memo has been the subject of intense debate in Congress, but the fight ratcheted up this week when the House Intelligence Committee voted along party lines to make the document public under a process that gives the president up to five days to block its release. The committee Republicans also voted not to release a Democratic rebuttal memo, saying they would allow that document to be made public in the future.
It is highly unusual for the White House and the FBI to be publicly at odds over a matter of national security, and it is unclear what impact the disagreement might have on the standing of FBI Director Christopher Wray and Deputy Attorney General Rod Rosenstein, two Trump appointees who went to the White House on Monday in an unsuccessful bid to urge that the memo not be released.
Law enforcement officials have expressed fear that Trump may try to use the memo's release as justification to fire Rosenstein, who is overseeing Special Counsel Robert Mueller and the Russia interference probe.
The chairman of the House Intelligence Committee, Rep. Devin Nunes, R-Calif., has accused the FBI of stonewalling lawmakers on matters related to the Russia probe for nearly a year.
"It's clear that top officials used unverified information in a court document to fuel a counter-intelligence investigation during an American political campaign," he said. "Once the truth gets out, we can begin taking steps to ensure our intelligence agencies and courts are never misused like this again."
The memo describes some of the details of how information from Steele, who compiled a controversial dossier of allegations against then-candidate Donald Trump, was used as part of an application to the FISA court to conduct surreptitious surveillance on Carter Page, a former Trump campaign adviser, according to people familiar with the matter.
The FBI statement said federal agents carefully adhere to the Foreign Intelligence Surveillance Act, which provides a legal framework for national security investigations.
"The FBI takes seriously its obligations to the FISA Court and its compliance with procedures overseen by career professionals in the Department of Justice and the FBI," the statement said. "We are committed to working with the appropriate oversight entities to ensure the continuing integrity of the FISA process."
