They also believe that Trump has a clear conflict of interest by trying to discredit an investigation in which he himself is a subject.
"The President shouldn't be declassifying documents in order to undermine an investigation into his campaign or pursue vendettas against political enemies", Warner said.
Thank you for signing up for the Top 3 Newsletter.
Democrats say the material is too secret for disclosure and object to any meddling in an ongoing investigation.
Democrats immediately opposed the President's move, accusing him of abusing his power.
The letter said, "Any decision by your offices to share this material with the President or his lawyers will violate longstanding Department of Justice policies".
The FBI obtained a Foreign Intelligence Surveillance Act warrant to spy on Page, who worked on Trump's campaign, in part by submitting a now questioned dossier compiled by former British intelligence official Christopher Steele for Fusion GPS.
"Really bad things were happening, but they are now being exposed".
"We're going to see", Trump told reporters Tuesday while meeting with his Polish counterpart at the White House, repeating his allegation that the investigation itself "is a witch hunt".
Senate Intelligence Chairman Richard Burr said Tuesday that he would prefer to keep the FISA documents on Page classified.More news: Jessica Simpson Is Expecting A Baby Girl and Baby Makes Five!
More news: 3.4M chickens, 5,500 hogs dead in Florence flood
More news: North and South Korea Vow to Denuclearize, Co-Host 2032 Olympics
The president is making the extraordinary move in response to calls from his allies in Congress who say they believe the Russian Federation investigation was tainted by anti-Trump bias within the ranks of the FBI and the Justice Department.
"He especially shouldn't be releasing documents with the potential to reveal intelligence sources".
"'This is not committees, this is Mark Meadows and Jim Jordan and a couple other members of Congress - who by the way haven't reviewed the information the way members of the Intelligence Committee have - but are just going to do everything in assisting the president's delegitimization of the Mueller investigation, '" it quoted Rep. Jim Himes, D-Conn., a member of the Intel Committee, as saying on MSNBC's 'Morning Joe'. "They have an obligation to be candid", said Kris, founder of Culper Partners consulting firm.
Burr previously broke with his House Intelligence Committee counterparts after they released a memo with details on the Page FISA.
Trump on Tuesday demanded the public release of "all text messages relating to the Russian Federation investigation" from James Comey, Andrew McCabe, Bruce Ohr, Peter Strzok, and his former lover Lisa Page.
Asked about a possible pardon for Manafort, Trump said: "I don't want to talk about it now".
There is no set timeline or format for the release of the materials at this time.
The FBI earlier released in heavily redacted format 412 pages of surveillance applications and court orders related to Page.
In his request on Monday, Trump requested the release of 21 pages from an application made by the Federal Bureau of Investigation in June 2017 to the foreign intelligence surveillance court for permission to continue surveilling Page. His communications were monitored for almost a year starting in October 2016. But in this case, he said the President has the unilateral authority to declassify.
"The danger (is that) decisions such as this, especially if they might appear to be politically motivated, suggest that the U.S. Government can't be trusted to keep its own secrets", said the official, speaking on condition of anonymity.