Kim Dong Chul, center, a U.S. citizen detained in North Korea, is escorted to his trial Friday, April 29, 2016, in Pyongyang, North Korea. A North Korean court has sentenced an ethnic Korean U.S. citizen to 10 years in prison for what it called acts of espionage. (AP Photo/Kim Kwang Hyon)
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Kim Dong Chul, center, a U.S. citizen detained in North Korea, is escorted to his trial Friday, April 29, 2016, in Pyongyang, North Korea. A North Korean court has sentenced an ethnic Korean U.S. citizen to 10 years in prison for what it called acts of espionage. (AP Photo/Kim Kwang Hyon)
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Story highlights

NEW: State media reports prosecutor demanded 15 years of hard labor, he was given 10

North Korea alleges Kim Dong Chul spied for South Korea to steal nuclear and military secrets

Kim is a South Korean-born American citizen

(CNN) —  

North Korea has sentenced a South Korean-born American citizen to 10 years of hard labor for subversion and espionage, a North Korean official told CNN.

Prosecutors were seeking a 15-year hard labor sentence for Kim Dong Chul for committing “offenses in a scheme to overthrow the socialist system of the DPRK,” according to state-run news agency KCNA.

The defense asked that Kim’s sentence be commuted, arguing “the crimes by the accused are very serious but he is old and may repent of his faults.”

Friday’s verdict was handed down by North Korea’s Supreme Court.

The U.S. State Department said it is aware of the media reports about Kim’s sentence.

“The welfare of U.S. citizens is one of the Department’s highest priorities,” State Department spokesman John Kirby said in an emailed statement.

“In cases where U.S. citizens are reported detained in North Korea, we work closely with the Swedish Embassy, which serves as the United States’ Protecting Power in North Korea. We have no further comment due to privacy considerations.”

Kim is the second American to receive a hard labor sentence from North Korea in the past two months.

A copy of Kim Dong Chul's passport provided by North Korea.
David Hawley/CNN
A copy of Kim Dong Chul's passport provided by North Korea.

In March, University of Virginia student Otto Frederick Warmbier was sentenced to 15 years of hard labor for allegedly removing a political banner from a Pyongyang hotel.

CNN’s Will Ripley spoke to Kim in January, under the watch of North Korean officials. Kim told CNN he used to live in Fairfax, Virginia, and had been in detention for three months.

Exclusive: North Korea reveals U.S. prisoner to CNN

Kim said he moved to Yanji, a Chinese city near the Chinese-North Korean border that acts as a trade hub between the two countries, in 2001. From Yanji, Kim said he commuted daily to Rason, a special economic zone on the North Korean side of the border, where he served as president of a company involved in international trade and hotel services.

Spying confession

According to Kim, he spied on behalf of “South Korean conservative elements” on the country’s nuclear and military program.

“I was tasked with taking photos of military secrets and ‘scandalous’ scenes,” he said at the time.

“They asked me to help destroy the (North Korean) system and spread propaganda against the government.”

North Korea launches two midrange missiles; both tests fail

Kim’s comments to CNN in January were