PYONGYANG, April 29 (Xinhua) -- The Supreme Court of the Democratic People's Republic of Korea (DPRK) on Friday sentenced a South Korea-born U.S. citizen to 10 years of hard labor for subversion of the DPRK social system and espionage activities.

Kim Dong-chul, who was born in 1953 in Seoul and immigrated to the United States in 1972, was charged with plotting to subvert the DPRK system, slandering the supreme leadership of the socialist country and gathering state and military secrets for espionage.

In 2005, Kim moved to Yanji, a Chinese city some 10 km from the border with the DPRK and later in 2008 established a trade company named Dongmyong in Rason, a special economic zone in North Hamgyong Province of the DPRK, where a large number of Chinese businesses operate.

After his company was founded, he continuously carried out reactionary propaganda against the DPRK and injected into local people fantasies about the superiority of the United States, in order to shaken the stability of the political and social system of the country, according to the prosecutor.

Kim started espionage in 2013 after coming into contact with several South Koreans who tasked him with collecting top party, state and military secrets of the DPRK, including its nuclear facilities, nuclear tests and photographs of warships as well as other information, inside the DPRK.

He was arrested on Oct. 2, 2015 when he was receiving an SD card that contained photos of local markets in Rason and documents about the DPRK's nuclear programs from a local resident in Rason whom he had bought off, said the prosecutor.

Kim confessed to the charges, repented of his crimes and appealed for gracious treatment in court.