Seoul:
South Korea's military scrambled naval vessels to the western waters near the disputed maritime border with rival North Korea late on Friday after an explosion ripped a hole in the bottom of a military ship, officials and news reports said.
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, 9:45 a.m. EDT), an official at the Joint Chiefs of Staff said, speaking on condition of anonymity in line with department policy.
South Korea's Yonhap news agency reported an explosion in the rear of the 1,200-ton ship and said the military had not ruled out the possibility of an attack by North Korea. However, the military official said the exact cause was not immediately clear and said he could not confirm the Yonhap report.
A rescue mission was under way and the military moved to strengthen its vigilance near the maritime border, the site of three bloody naval clashes in the past 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 on Friday, North Korea's military threatened "unpredictable strikes," including a nuclear attack, in anger over a report that South Korea and the US were preparing for possible instability in the totalitarian country.
After the ship began sinking, President Lee Myung-bak convened an emergency meeting of security-related ministers, Yonhap said, citing presidential spokeswoman Kim Eun-hye. She said it wasn't clear yet whether North Korea was involved in the ship's demise.
Six naval ships and two coast guard vessels were rushed to the waters to save the crew, Yonhap said. Rescue helicopters and ambulances also sped to the scene, the military official said. By 12:30 a.m. Saturday (1430 GMT, 10:30 a.m. EDT Friday), with the ship nearly submerged, 58 of the soldiers had been rescued, the official said. There was no immediate confirmation of any casualties.
Yonhap reported earlier that a South Korean ship fired shots toward an unidentified target in the direction of North Korea. The military official confirmed that shots were fired but said the object detected by radar may have been a flock of birds.
Baeknyeong Island, four hours' by boat from the port of Incheon, is the westernmost point of South Korea and is a key military post for South Korea because of its proximity to the North.