Just what we need.

The waters around Baeknyeong island are rocky, and some senior government officials speculated that the sinking may have been an accident, not an attack, South Korean media said.

"It's looking more and more like it was just an accident that happens on a ship," Carl Baker, an expert on Korean military relations at the Pacific Forum CSIS think tank in Honolulu, said by telephone.

He said Pyongyang was unlikely to attack the far more powerful South Korean military.

"The South Koreans are so much more capable these days than the North that it would be difficult for the miscalculation to happen because I think the North understands its lack of ability," he said.