PYONGYANG, March 25 -- A South Korea-born U.S. citizen held by the Democratic People's Republic of Korea (DPRK) confessed in public to committing anti-DPRK crimes Friday.

Kim Dong-chul, born in 1953 in South Korea, told a press conference that he tried to gather DPRK top military and state secrets and subvert its government under leader Kim Jong-un.

Kim, who immigrated to the United Statesin 1972, moved to Yanji, a border city between China and the DPRK, in 2005 and later in 2008 established a trade company in Rason, a special economic zone in North Hamgyong Province of the DPRK, where large numbers of Chinese businesses operate.

Kim pledged that during his time in Rason he "defamed the DPRK social system, carried out reactionary propaganda and tarnished the supreme dignity of the country in a systematic manner, in order to undermine the single-minded unity of the DPRK people," using vocabulary similar to that of DPRK official rhetoric.

He said he "insulted his employees who would laud the DPRK's leadership and propagandized the collapse of the DPRK system as well as instilled fears for the war to be waged by Washington into his local staff."

According to Kim's confession, he started "espionage activities" in 2013 after coming into contact with several South Koreans who tasked him with gathering information on the DPRK's top leadership, nuclear facilities, military secrets, national economy, naval vessels that were being built as well as the DPRK's latest political and economic policies.

He said he was also asked to photograph the poor living standards of the locals.

Kim was caught on Oct. 2, 2015 when he was receiving a flash disk and other documents, which he said contained military secrets, from a local resident in Rason whom he had bought off.

He said he "perpetuated the crimes because South Korea and the United States where he was brought up instilled into him American values and hatred and resentment against the DPRK."

He apologized for all his crimes and said he would accept any punishment while begging for an opportunity for self-correction.

The DPRK government convicted a number of foreigners of anti-DPRK crimes in recent years, often letting them publicly confess their actions before trying them in court.

Last week, American student Otto Frederick Warmbier was sentenced to 15 years of hard labor for taking down a political slogan from a hotel.

In December 2015, the Supreme Court of the DPRK sentenced South Korea-born Canadian pastor Hyeon Soo Lim to lifetime labor. He was charged with attempts to overthrow the DPRK government and undermine its social system under the guise of conducting religious exchanges over 18 years.

In late 2014, Pyongyang released three detained Americans, two of whom had been sentenced to hard labor of six years and 15 years respectively, for "hostile acts against the DPRK."