Almost 70 percent of the Democratic People's Republic of Korea's submarines were undetected on Sunday, with the second round of high-level contact under way in the truce village of Panmunjom, a Defense Ministry official of the Republic of Korea was citied as saying.

Some 50 DPRK submarines, which left bases in the western and eastern coasts, have been out of detection range of the ROK military, which estimated the DPRK had a total of 70 submarines.

The 70 percent was 10 times the rate under normal situations and also the highest since the three-year Korean War ended in 1953.