By David Ingram

WASHINGTON (Reuters) - A former U.S. State Department analyst pleaded guilty on Friday to sharing secret information about North Korea with a reporter for Fox News, becoming the latest government employee convicted in a campaign against unapproved leaks to the media.

Stephen Kim, 46, entered the plea in U.S. District Court to avoid a trial scheduled for April. Under an agreement with prosecutors, he admitted to the unauthorized disclosure of U.S. national defense information but will not face a charge that he lied about the leak to the FBI. Kim's attorneys and prosecutors agreed on a sentence of 13 months in prison, but that is subject to the approval of Judge Colleen Kollar-Kotelly. She scheduled sentencing for April 2.

The case is one of 11 times in U.S. history that prosecutors have brought charges for disclosing information to a newspaper, blog or other media outlet. Eight cases have been brought since President Barack Obama took office in 2009.

After Kim's court hearing, his attorney Abbe Lowell issued a statement attacking the case as unfair. "Lower-level employees like Mr. Kim are prosecuted because they are easier targets or often lack the resources or political connections to fight back. High-level employees leak classified information to forward their agenda or to make an administration look good with impunity," Lowell said.

The case took a toll on Kim's family that rivaled what some of them went through as Korean War refugees, a sister, Yuri Lustenberger-Kim, said in a separate statement.

"The decision to plead has been the most wrenching, painful decision in our collective family experience," she said.

Kim is a U.S. citizen who was born in Seoul and has a doctorate in history. He was not accused of stealing secrets or of working as a spy on behalf of another government, but he also did not claim to be blowing the whistle on U.S. government fraud or misconduct. Instead, prosecutors said Kim let his guard down too far with reporter James Rosen and shared information about North Korea's military capability and preparedness that was top secret.

On June 11, 2009, they spoke briefly by phone and then met outside the State Department, where Kim was on contract as a senior adviser with top secret clearance. Later that day, Rosen reported on Fox News' website that North Korea was planning a nuclear test in response to heightened sanctions. Investigators used phone records and security logs to piece together the meeting. A grand jury indicted Kim in 2010.

"We will not waver in our commitment to pursuing and holding accountable government officials who blatantly disregard their obligations to protect our nation's most highly guarded secrets," the chief prosecutor, U.S. Attorney Ronald Machen, said in a statement after the court hearing. Without specifying what damage Kim might have caused, prosecutor Michael Harvey said in court that the leak could have harmed U.S. national security or been used by other governments.

Lowell said in his statement that Kim did not reveal intelligence sources or methods, and that the information was nothing significant.

The FBI interviewed Kim about the Fox News report, and according to the FBI, Kim lied about having spoken with Rosen. Lowell in court disputed the charge, but it was dropped as part of the plea agreement. The maximum penalty Kim faces under the law is 10 years. In developments last year that drew outcry from advocates for press freedom, the FBI obtained Rosen's emails as part of its investigation into Kim and described Rosen in a search warrant affidavit as a possible criminal co-conspirator.

Rosen was never charged, and the Justice Department said there were no plans to charge him.

On Obama's orders, the Justice Department revised its guidelines and said it would not seek search warrants against journalists for carrying out "ordinary news-gathering activities."

Representatives for Fox News were not immediately available to comment on Friday.

(Additional reporting by Jennifer Saba; Editing by Howard Goller)