Attorney General Eric Holder, in a letter to the House Judiciary Committee, maintains that he didn't lie to members of Congress when he said that the Justice Department was not moving to prosecute journalists who publish classified information.

Eric Holder (AP Photo) Eric Holder (AP Photo)

House Republicans have opened a perjury inquiry, arguing that Holder's statement doesn't square with the department's labeling of Fox News reporter James Rosen as a potential "co-conspirator" in court documents used to monitor Rosen.

"I do not agree that characterizations establishing probable cause for a search warrant for materials from a member of the news media during an ongoing investigation constitute an intent to prosecute that member of the news media," Holder wrote. "I do believe that a thorough investigation of the disclosure of classified information that threatened national security was necessary and appropriate."

He added: "As explained in our prior letters, the government’s decision to seek this search warrant was an investigative step, and at no time during this matter have prosecutors sought approval from me to bring criminal charges against the reporter.”

Holder said at a May hearing that he was not aware of any potential criminal cases being brought against journalists.

“With regard to the potential prosecution of the press for the disclosure of material: that is not something I’ve ever been involved in, heard of or would think would be wise policy,” he said.

That comment earned scrutiny after the Washington Post reported that the Justice Department had been monitoring Rosen over a 2009 report on Iran. In order to get the surveillance approved by a court, the Justice Department labeled Rosen a potential "co-conspirator."

Holder and the Justice Department have said, in spite of that language, Rosen was never a target for prosecution.