A U.S. citizen detained in North Korea confessed Friday to his crime of espionage in connection with South Korea's spy agency and asked for mercy, the North's state media said.
   
Kim Dong-chul, a 62-year-old U.S. citizen, said at a press conference in Pyongyang that he has been serving as a spy for South Korea by secretly passing on intelligence on the North's party and military to Seoul, according to the Korean Central News Agency (KCNA).
  
Kim was detained by the North after being arrested in October last year while receiving a USB and documents related to the North's nuclear and military secrets from someone in the North's border city of Rason, it said.
   
The report came more than one week after a U.S. college student detained in the North was sentenced to 15 years of hard labor on charges of state subversion.
   
On March 16, North Korea's supreme court handed down the ruling to Otto Warmbier on charges of his subversive acts of stealing a propaganda sign at a hotel.
  
Experts said the North has previously used detained Americans as leverage to force the U.S. to open bilateral talks with it.
   
The North is under pressure as the United Nations Security Council imposed tougher sanctions against North Korea earlier this month over its nuclear test and long-range rocket launch.
   
In 2014, Pyongyang released three detained Americans -- Kenneth Bae, Matthew Todd Miller and Jeffrey Fowle.
  
Lim Hyeon-soo, a Korean-Canadian pastor, has also been held in captivity in the North since he entered the country via China on a humanitarian mission in January 2015.
  
In December, the North's highest court sentenced Lim to life in prison, citing his "subversive plots" against the North's regime. (Yonhap)