Not good.
S. Korea on alert as N. Korean subs disappear in East Sea
SEOUL, May 26 (Yonhap) -- South Korea's military was tracking four North Korean submarines which disappeared from their east coast base after conducting naval training in the East Sea earlier this week, a military official in Seoul said Wednesday.
Locations of the North's four 300-ton-class submarines have been unknown for two days, the military official said, noting, "We are tracking the four submarines by mobilizing all naval capabilities in the East Sea."
The submarines left the Chaho base located near the Musudan-ri missile launch pad site in North Hamgyong province in North Korea's northeast coast, according to the official.
Tensions on the Korean Peninsula flared after a multinational investigation concluded last week that a North Korean submarine slipped into the South's waters near their Yellow Sea border and attacked a South Korean warship with a torpedo, killing 46 crew members on March 26.
A slew of military measures announced this week by the South's government include an anti-proliferation sea drill targeting the North's weapons traffic, joint anti-submarine and maritime drills with the U.S. and a resumption of psychological warfare against the North.
North Korea, which denied any involvement in the sinking, has threatened to cut all inter-Korean relations and wage an "all-out war" in response to any punishment attempts.
http://english.yonhapnews.co.kr/news/2010/05/26/0200000000AEN20100526001200315.HTML