South Korea said Tuesday it will continue all-out efforts to bring home four South Koreans detained in North Korea, including a New York University student, as soon as possible.



Joo Won-moon, a 21-year-old student, has been detained by North Korea since April 22 after illegally entering the country by crossing the Amrok River through a Chinese border city. Joo is a South Korean national with a U.S. green card.



North Korea has also kept in captivity three other South Koreans, including missionary Kim Jung-wook.



The Ministry of Unification held a meeting with other related government agencies last week to discuss ways to win their release.



"The government will do its best to secure the safety of our nationals and to bring them home as soon as possible," said a ministry official, asking not to be named.



He declined to elaborate on what specific efforts Seoul will make.



In a recent interview with U.S. news cable network CNN, Joo admitted that he intentionally entered the communist country on the belief that his arrest could have a good effect on inter-Korean relations.



Missionary Kim, 52, has been held there since October 2013. The North has described him as a spy of South Korea's National Intelligence Service, who sneaked into the country with the purpose of inciting dissent.



The other two detained South Koreans -- Kim Kuk-gi and Choe Chun-gil -- were recently allowed to have separate interviews with CNN, in which they said they worked for Seoul's spy agency. CNN said it hasn't been able to independently verify their accounts. (Yonhap)