A Korean-American scientist was released from prison Tuesday after serving 10 months on a conviction of passing classified information about North Korea to a reporter in a case that has sparked criticism that the U.S. government applied double standards.

Stephen Kim, 47, was sentenced in April last year to 13 months in prison for passing information about the possibility of North Korea conducting a nuclear test to a Fox News reporter in 2009. Kim began serving the prison term in July.

Kim later got his sentence reduced by two months for exemplary behavior, and had another month taken off the term as he checked into a halfway house after release, a place that is meant for reintegration of a person who has served in prison.

"I'm so grateful and proud of my brother putting up with nearly 10 months of difficult time," Kim's sister, Yuri Lustenberger-Kim, told Yonhap News Agency by phone from Zurich, where she lives. "I hope people around him will provide him with a lot of help and support so that he can chart a new life."

Supporters of Kim have claimed that his punishment was too harsh, considering the information he passed to the reporter is not highly sensitive nor based on concrete intelligence, but just common-sense information that anyone could discern.

In March, Kim's lawyer demanded his immediate release, strongly accusing the U.S. Justice Department of a "profound double standard" after the department recommended only a misdemeanor conviction for a former CIA director charged with a similar offense.

Former CIA Director David Petraeus was accused of giving classified materials to Paula Broadwell, his mistress and biographer, while he held the top job at the CIA, but the Justice Department decided to permit him to plead guilty to a misdemeanor.

Petraeus was also charged with giving Broadwell several notebooks that contained highly classified information he had compiled during his time as a top general, including the identities of covert officers, war strategy and intelligence capabilities. (Yonhap)