McCabe has said in the past that the FBI had a good reason to launch a counterintelligence investigation into whether Trump was working with Russia and was a possible national security threat.
The former official was asked on CNN’s "Anderson Cooper 360" if he believes Trump may still be a Russian asset. He said he’s "anxious" to see the conclusion of Special Prosecutor Robert Mueller’s investigation.
Kellyanne Conway, the White House counselor, told the network that McCabe's comment is "hardly [worth] dignifying with a response."
"He's a liar and a leaker," she said.
McCabe was also asked if he believes Trump is fit to serve. He said it was not up to him to make the determination.
On Sunday, McCabe told CBS News’ “60 Minutes" that he met with investigators after ex-FBI Director James Comey’s firing.
"I was very concerned that I was able to put the Russia case on absolutely solid ground, in an indelible fashion,” McCabe said. "That were I removed quickly, or reassigned or fired, that the case could not be closed or vanish in the night without a trace."
He added, "I wanted to make sure that our case was on solid ground and if somebody came in behind me and closed it and tried to walk away from it, they would not be able to do that without creating a record of why they made that decision."
McCabe was fired from the Justice Department last year after being accused of misleading investigators during an internal probe into a news media disclosure. Trump has slammed McCabe over Twitter, accusing the ex-official of plotting a coup with Deputy Attorney General Rod Rosenstein.