FBI Director James Comey on Wednesday refused to confirm to the Senate Judiciary Committee whether the FBI is investigating how the transcript of a phone call between former national security adviser Mike Flynn and a foreign official was leaked to the public.

"Without getting into any particular article, is there any investigation of any leaks of classified information relating to Mr. Trump or his associates?" Committee Chairman Chuck Grassley, R-Iowa, asked him.

"I don't want to answer that question, senator, for reasons I think you know," Comey responded. "Leaks are always a problem, especially in the last three to six months."

Comey also testified he had never been an anonymous source for any news reports.

Grassley's line of questioning tightly summed up the Republican angle of questioning in the FBI oversight hearing, as the GOP is pushing for answers on how information about Flynn's discussions were leaked. Democrats, in the meantime, pushed Comey on Russia's interference with the election.