Trump says no collusion; GOP and Dem members say case isn’t closed

President Donald Trump makes remarks prior to signing an "Antiquities Executive Order" at the Department of the Interior, on April 26, 2017 in Washington, DC. Interior will review prior monument designations made by former Presidents Barack Obama, George W. Bush and Bill Clinton. (Photo by Mike Theiler-Pool/Getty Images)

(CNN) — Possible collusion between Trump associates and Russians remains a subject of investigations by the House and Senate intelligence committees, contrary to assertions from President Donald Trump and White House officials that there’s no evidence of collusion, multiple sources in both parties tell CNN.

“The committee is drawing no conclusions at this time, and will continue to follow the facts where they lead,” GOP Sen. Richard Burr, the chairman of the Senate intelligence committee, told CNN.

Such possible collusion is “the whole underlying premise of the investigation,” a House Democratic source involved in the investigation said.

Another member of the Senate committee told CNN that possible collusion “is what we are investigating.”

In his termination letter to FBI Director James Comey on Tuesday, Trump wrote, “I greatly appreciate you informing me, on three separate occasions, that I am not under investigation.” The President has long insisted the investigation will not discover any wrongdoing.

Earlier, following Monday’s Senate judiciary subcommittee hearing on Russian interference in the US election, Trump tweeted, “The Russia-Trump collusion story is a total hoax, when will this taxpayer funded charade end?”

He also tweeted, “(former Director of National Intelligence James) Clapper reiterated what everybody, including the fake media already knows- there is “no evidence” of collusion w/ Russia and Trump.”

The tweet appeared to be referencing Clapper’s answer to a question from Sen. Lindsay Graham, the chairman of the subcomittee, as to whether he had seen evidence of collusion. He answered that he had not.

Asked the same question by Graham, the former acting Attorney General Sally Yates, declined to answer, saying, “Senator, my answer to that question would require me to reveal classified information and so I can’t answer that.”

In testimony before the House intelligence committee in March, Comey testified that the FBI was investigating possible collusion between Trump associates and Russian officials and other Russians known to US intelligence as part of its broader, ongoing counter-intelligence investigation.

In addition to the FBI, four congressional panels continue to investigate Russia and Russian election interference, the Senate and House intelligence committees, the Senate Judiciary subcommittee on Crime and Terrorism, which held the hearings Monday, and the House oversight committee.

Intelligence officials tell CNN that Clapper, as a matter of policy, would not be involved in an investigation of possible collusion between Trump associates and Russia because US intelligence agencies are barred by law from probes involving US persons.

CNN has previously reported that the FBI obtained a Foreign Intelligence Surveillance Act warrant regarding Carter Page, a one-time policy adviser to then-candidate Trump, as part of its ongoing probe.