Except in unusual circumstances, newspapers rarely comply with such requests because journalists typically try to steer clear of doing anything that can be seen as working with the governmental agencies they cover.
Since October, the Tribune has broken several stories on the Blagojevich probe, but in some cases withheld information because of the government's request.
Conversations began when Tribune reporters investigating allegations of misconduct involving Blagojevich uncovered certain aspects of the U.S. attorney's criminal probe, said Tribune editor Gerould Kern.
"Our reporters contact individuals involved in these stories for confirmation and comment prior to publication. Consequently, we contacted the U.S. attorney's office in the course of our reporting," Kern said in a statement.
"On occasion, prosecutors asked us to delay publication of stories, asserting that disclosure would jeopardize the criminal investigation. In isolated instances, we granted the requests, but other requests were refused," Kern said.
In a news conference Tuesday, Fitzgerald said Tribune reporters called his office for comment on a story about part of the probe eight weeks ago, prompting prosecutors to ask the paper not to publish some elements of the story.
"We thought we'd never have the opportunity to install the bug or place the telephone tap and we made an urgent request for the Tribune not to publish that story," Fitzgerald said. "That is a very rare thing for us to do and it's an even rarer thing for a newspaper to grant.
"I have to take my hat off that the Tribune withheld that story for a substantial period of time, which otherwise might have compromised the investigation from ever happening," he said.