Transcript for James Comey to publicly testify before the Senate

much. The latest on the Russia investigation. New questions this morning about president trump's meeting with Russian officials and what he said about former FBI director James Comey. Our senior justice correspondent Pierre Thomas has more and joins us with those details. Good morning. Reporter: Robin, good morning. Allegations of name-calling from president trump only likely to fuel the war of words with the former FBI director set to testify before congress in the coming weeks. Even as the president travels oversea, questions about Russia and the firing of the FBI director remain front and center. These questions need to be answered. Reporter: New reports say federal investigators are looking into whether there were ties between the trump campaign and Russia are interested in a white house staffer. The staffer has not been identified and it's unclear what the investigators want. I don't know where it will go. Again, we got to step back and let the investigators and the FBI and the others do their job. Reporter: Newly appointed special counsel Bob Mueller is gearing up for an investigation and many who know him say it will be broad and aggressive. This is fired FBI director James Comey preparing to testify before the senate intelligence committee. "The New York Times" reporting president president trump allegedly called him a nut job in the oval office during that meeting with top Russian officials reportedly adding that firing Comey took great pressure off him. Is that what the president said. Well, I don't remember exactly what the president said, the gist of the conversation was that the president feels as if he's hamstrung. Reporter: The investigation into Russia is not going anywhere and with the testimony it of Comey on the horizon, more dramatic moments surely to come, George. Okay, Pierre, thanks very much.

This transcript has been automatically generated and may not be 100% accurate.