North Korea sentenced a South Korean missionary to life with hard labor on Friday after convicting him of espionage and setting up an underground church.

North Korea's official KCNA news agency reported that the South Korean, identified as Kim Jong Uk, had admitted his guilt at a court trial held on Friday.

The ruling followed a recent exchange of fire between forces of the tightly controlled communist North and democratic South Korea. Both sides are still technically at war since the 1950-53 conflict ended in a truce.

"The accused admitted to all his crimes. He tried to infiltrate into Pyongyang after illegally trespassing on the border for the purpose of setting up underground church and gathering information about the internal affairs" of North Korea, the news agency said. It also accused Kim of trying to encourage North Koreans to flee to the south and of organizing a spy network.

Kim, a South Korean Christian missionary, was put on show at a televised event in February and confessed to spying for the the South Korean intelligence agency and promoting his church activities. Pyongyang has rejected calls from Seoul for his release and for his family to visit him.

Earlier this month, Seoul accused North Korea of firing two artillery rounds across their maritime border near a South Korean navy patrol ship. They did not hit the vessel, and South Korea replied with several rounds.

North Korea is still holding Kenneth Bae, a Korean-American missionary sentenced to 15 years of hard labur on charges of trying to use religion to overthrow its political system.

The isolated country has twice cancelled visits by Robert King, the U.S. special envoy for North Korean human rights issues, to discuss Bae's case.