South Korean Military on alert as S Korean warship sinks near North Korea

South Korean Military on alert as S Korean warship sinks near North Korea:

A South Korean naval ship sank near the disputed maritime border with North Korea early Saturday, prompting the South's military to rush vessels to the site to rescue its sailors and raising fears of an attack by the North.

The ship, on a routine patrolling mission with 104 crew members on board, began sinking off the coast of South Korean-controlled Baengnyeong Island close to North Korea around 9:45 p.m. (1245 GMT, 8:45 a.m. EDT), Rear Adm. Lee Ki-sik of the Joint Chiefs of Staff told reporters late Friday.

Lee said an unexplained hole in the bottom of the ship caused the vessel to take on water. South Korea's Yonhap news agency reported that the ship was damaged by an explosion, and said the military had not ruled out the possibility of an attack by North Korea.

A rescue mission was under way. Officials told Yonhap there were some deaths among the sailors but did not specify the number. The military, meanwhile, moved to strengthen its vigilance near the maritime border, the site of three bloody naval clashes between the warring Koreas. The divided peninsula remains in a state of war because the three-year Korean conflict ended in a truce, not a peace treaty, in 1953.

Earlier Friday, North Korea's military threatened "unpredictable strikes," including a nuclear attack, in anger over a report that South Korea and the U.S. were preparing for possible instability in the totalitarian country.

Red arrow points to Baengnyeong Island.

UPDATE: FoxNews reporting damage self- inflicted. AFP identifies unit as "Patrol Combat Corvette PCC-772 Chonan."