Friday's Navy ship sinking might be caused by mine explosion, South Korean media YTN quoted presidential sources as saying on Saturday.

General of the South Korean Navy Lee Ki-shik said later Friday that the 1,200-ton warship Cheonan went down after the unexplained explosion ripped a hole in the ship's bottom.

Officials have narrowed down the possibilities of the Democratic People's Republic of Korea (DPRK)'s involvement in the incident, local media earlier reported.