51.   Seoul officials say the submarine was on a spy mission and are demanding an apology from their North Korean rivals.

52.   Seoul believes the submarine was on a spy mission, while Pyongyang says it ran aground by accident.

53.   That submarine was almost twice as large as the one captured Monday.

54.   South Korea believes the submarine was on a spy mission, while the North says it ran aground by accident after developing engine trouble.

55.   South Korea believes the submarine was on a mission to land spies and saboteurs.

56.   South Korea claims the submarine was on a spy mission.

57.   South Korea says the shark-class submarine was on a spy mission.

58.   South Korea says the submarine was on a mission for surveillance and sabotage.

59.   Submarines were the only means of defense of the West Coast in the early part of the century, Dodd said.

60.   Such submarines are very quiet and almost impossible to detect, even with sophisticated equipment.