Speaking Sunday on ABC News, Schiff called the GOP memo a "political hit job on the FBI in service of the president."
"The goal here really isn't to find out the answers from the FBI. The goal here is to undermine the FBI, discredit the FBI, discredit the [special counsel] investigation, do the president's bidding," Schiff said on "This Week."
Democrats spent the weekend pushing back against the claim by President Trump and some Republicans that corruption has poisoned the investigation led by special counsel Robert S. Mueller III into possible coordination between the Trump campaign and the Kremlin during the 2016 election. Democrats and some Republicans worry that this view, buttressed by the GOP memo, will lead Trump to fire Mueller or Deputy Attorney General Rod J. Rosenstein, who oversees the Russia probe.
Calling on Trump not to interfere in Mueller's investigation, four Republican members of the House Intelligence Committee dismissed on Sunday the idea that the memo's criticism of how the FBI handled certain surveillance applications undermines the special counsel's work. Reps. Trey Gowdy (S.C.), Chris Stewart (Utah), Will Hurd (Tex.) and Brad Wenstrup (Ohio) represented the committee on the morning political talk shows.
Gowdy, who helped draft the memo, said Trump should not fire Rosenstein, and he rejected the idea that the document has a bearing on the investigation.
"I actually don't think it has any impact on the Russia probe," Gowdy, who also chairs the House Oversight Committee, said on CBS's "Face the Nation."
Stewart, arguing that the two are "very separate" issues, said Mueller should be allowed to finish his work. "This memo, frankly, has nothing at all to do with the special counsel," he told "Fox News Sunday."
The four Republicans walked a careful line on the GOP document, which alleges that the Justice Department abused its powers by obtaining a warrant for surveillance of former Trump campaign adviser Carter Page using information from a source who was biased against Trump. Their comments echoed those of Speaker Paul D. Ryan (R-Wis.), who supported the memo's release but insists that its findings do not impugn Mueller or Rosenstein.
House Intelligence Committee Chairman Devin Nunes (R-Calif.), whose actions have been at the center of the debate over the memo, did not give interviews Sunday.
It remained unclear Sunday whether Trump would use the document as a pretext to fire senior Justice Department officials, a decision that could trigger a constitutional crisis, according to Democrats. Trump advocated the memo's release, telling advisers it could help him, in part by undercutting Mueller's investigation and opening the door to firings.
Trump tweeted Sunday that while "the Russian Witch Hunt goes on and on," the Republican memo "totally vindicates" him.
"Their [sic] was no Collusion and there was no Obstruction (the word now used because, after one year of looking endlessly and finding NOTHING, collusion is dead). This is an American disgrace!" he wrote from Florida, where he spent the weekend.
The four-page GOP memo accused current and former senior Justice Department officials of omitting key facts about former British intelligence officer Christopher Steele, the source of some of their information, in applications to carry out surveillance on Page. Steele wrote the now-infamous dossier alleging ties between Trump and Kremlin officials; his research was paid for by Hillary Clinton's presidential campaign and the Democratic National Committee.
Republicans say this funding stream should have been disclosed in the surveillance applications, which they argue would not have been approved without the information contained in the dossier. Democrats take issue with both points.
Nunes said Friday that Justice "got a warrant on someone in the Trump campaign using opposition research paid for by the Democratic Party and the Hillary Clinton campaign."
"That's what this is about," he told Fox News. "And it's wrong. And it should never be done."
If the House Intelligence Committee approves the release of the Democratic memo, it is expected to go to the Justice Department for redactions. Even if the motion succeeds, Trump has five days to block it.
Senate Minority Leader Charles E. Schumer (D-N.Y.) urged the president to support the document's release in the spirit of fairness.
"A refusal to release the Schiff memo . . . will confirm the American people's worst fears that the release of Chairman Nunes' memo was only intended to undermine Special Counsel Bob Mueller's investigation," Schumer wrote Sunday in a letter to Trump.
The Intelligence Committee voted along party lines last week to release the Republican memo despite warnings from national security officials that it would damage U.S. law enforcement.
As Sunday's back-and-forth set the stage for more heated debate this week, Republicans faced questions over whether Trump might fire Mueller or Rosenstein.
Reince Priebus, the former White House chief of staff, said Sunday that he "never felt that the president was going to fire the special counsel," disputing a report in The Washington Post that he was "incredibly concerned" Trump was moving to fire Mueller last summer.
"I never heard that," Priebus said on NBC's "Meet the Press." Pressed on whether he was aware of the president's views on the issue, Priebus said Trump was clear about what he saw as Mueller's conflicts of interest in the job, and he allowed that others may have "interpreted that" as Trump's desire to fire Mueller.
Former White House communications director Anthony Scaramucci told ABC's George Stephanopoulos that Trump should not fire Rosenstein.
"I would tell the president, if I was in his presence, 'Do not fire him," he said. "He'll be fair and impartial. You may be upset about the politicization of what happened, but I don't think it came from him. Give him a chance to sort this out with the rest of the department.' "
Scaramucci also said he hopes Trump decides not to testify before Mueller in the probe of Russian interference in the 2016 election.
"I actually don't want him to testify, because as a lawyer, I don't want him caught in a 'gotcha' moment where someone accuses him of lying, where he may not remember something. . . . I would say, 'Sir, there's no reason to testify. Let the thing unfold the way it is.' "