SEOUL, South Korea — An American detained in North Korea said he had spied against the country and asked for forgiveness at a media presentation Friday, nine days after a U.S. tourist was sentenced to 15 years in prison with hard labor for subversion.

Kim Tong Chol told a press conference in Pyongyang that he had collaborated with and spied for South Korean intelligence authorities in a plot to bring down the North’s leadership and tried to spread religious ideas among North Koreans.

Kim was born in South Korea and became a naturalized U.S. citizen. In an interview with CNN in January, Kim said he lived in Fairfax, Va., before moving in 2011 to Yangji, a city near the Chinese-North Korean border. He said he commuted daily to Rason, a special economic zone in North Korea, where he was president of a trade and hotel services company.

North Korea often arranges press conferences for detainees in which they read statements to acknowledge their wrongdoing. Those detainees have said that they were coached or coerced on what to say.