WATCH: Rubio has 'significant doubts' on 'criminality' of Trump, Comey Feb. 14 meeting

Sen. Marco Rubio (R-Fla.) has "significant doubts" that President Trump broke the law by reportedly asking then-FBI Director James Comey to let go of an investigation into former national security adviser Michael Flynn.

"I don't think anybody would leave this hearing and say to you that what the president said in the Oval Office on the 14th of February was appropriate. Whether it rises to criminality, I think there's significant doubts about what rises to that level," Rubio told reporters following Comey's testimony before the Senate Intelligence Committee.

Rubio was one of several senators on the Intelligence Committee who spoke with reporters between Comey's public hearing and a shorter, classified meeting with the former FBI director.

Asked if there was evidence that Trump obstructed justice, Democratic Sen. Martin Heinrich (N.M.) said, "I think there's enough there that we should be very concerned about what went on."

Rubio seized on Comey's revelation that he asked a friend to leak to the media memos detailing his one-on-one meetings with Trump.