Sen. Mark Warner of Virginia, the ranking Democrat on the Senate Intelligence Committee, says that President Trump's congressional allies are playing "fast and loose" with confidential information amid threats of exposing the identity of a reported FBI informant who interacted with Trump campaign officials in 2016 while the bureau looked into potential ties between the Russia government and members of the campaign.

"I find it outrageous that the president's allies are in effect playing fast and loose with confidential information. And don't take my word, take the president's own FBI director, [Christopher] Wray, who said, if you go out and start exposing classified information about informants that you will make America less safe," Warner told CBS News' "Face the Nation" on Sunday.

Warner's comments follow reporting by both the New York Times and Washington Post on the informant's role in the Russia investigation.

On Friday, Mr. Trump tweeted that the FBI "implanted" a "spy" in his campaign after a National Review article speculated about the possibility last week. On Saturday, he again tweeted about the possibility of the DOJ and FBI "infiltrating" his campaign, saying that only with the release of classified documents from congressional investigators would "give the conclusive answers."

Warner said that even though he has "no information that would indicate that the president's tweets or theory of the case is at all based in truth, I do know this: That classified information, identity of agents is sacrosanct."

The Washington Post reported Thursday that members of Mr. Trump's inner circle are now ramping up pressure to expose the role of the secret FBI source, effectively undermining the special counsel's investigation. But the Post said it didn't publish the name after U.S. intelligence officials said doing so might endanger the source or the source's connections.

While Warner said he has "no knowledge" of such actions being taken during the campaign, he told "Face the Nation" on Sunday that when individuals want to reveal classified information about the identity of an FBI or CIA sources, that's against the law.

"The first thing you learn when you get involved with the intelligence community is that you need to protect sources and methods and that if you were to out or to burn such an agent, that person's life could be in jeopardy," warned Warner.

Warner warned of an "ongoing assault" from Mr. Trump and his allies against the intelligence community, saying that it leads to an era where "people can start saying I'm going to decide which laws I want to follow and which laws I don't want to follow."

"I believe you may see that kind of result taking place in this circumstance where it appears that some of the president's allies are trying to decide, well, I don't want to follow a law that says I have to keep classified information secret. If we get into that realm we're in dangerous, dangerous territory," added Warner.