Trump told The New York Times last week that he believed Rice could be guilty of a crime. Her spokesman told ABC News she wouldn't "dignify the president's ludicrous charge with a comment."
Fox Business host Maria Bartiromo asked Trump why he has so many Obama officials remaining in his administration, specifically Comey, who is not technically a political appointee.
Asked whether it was "too late" to get rid of Comey, Trump appeared hesitant to discuss the matter.
"No, it's not too late," Trump said. "But you know, I have confidence in him. We'll see what happens. It is going to be interesting."
He went on to hit Comey for his actions in the investigation into Hillary Clinton's use of a private email server when she was secretary of state, saying he was "very, very good to her" and "if he weren't, she would probably be going to trial."
Comey said last summer that his agency did not recommend that charges be brought against her, after a yearlong investigation.
Trump, asked whether he's considering taking any further action against Clinton, said, "I don't want to talk about that. I want to talk about positive things."
Trump previously backed away from campaign threats to appoint a special prosecutor to investigate the issue.
