“I was concerned that there appeared to be in the media a number of stories that might have been based on communications reporters or non-reporters like Rudy Giuliani were having with people in the New York field office,” Mr. Comey said in a transcript of his Friday appearance before the House Judiciary and Oversight committees that was released Saturday.

Mr. Giuliani didn’t immediately respond to a request for comment, but has previously denied getting information from anyone in the New York field office. He said he heard rumors about the Clinton investigation from retired FBI agents as well as from media reports.

“Mr. Giuliani was making statements that appeared to be based on his knowledge of workings inside the FBI New York,” Mr. Comey said. “And then my recollection is there were other stories that were in the same ballpark that gave me a general concern that we may have a leak problem—unauthorized disclosure problem out of New York, and so I asked that it be investigated.”