1.   That indicated, Chung said, that the sub was on an infiltration mission.

2.   But the South Korean defence ministry quoted the sole prisoner taken alive as saying the sub was on an infiltration mission to drop off and pick up reconnaissance agents.

3.   But the South Korean defense ministry said the sub had been on an infiltration mission to drop off and pick up reconnaissance agents.

4.   But the South refused, saying the sub had been on an infiltration mission to drop off and pick up reconnaissance agents.

5.   The sole prisoner said the sub was on an infiltration mission to drop off and pick up reconnaissance agents.

6.   The South Korean defence ministry has quoted the sole prisoner taken alive as saying the sub was on an infiltration mission to drop off and pick up reconnaissance agents.

7.   Ri Kwang-Su, the sole prisoner, has told interrogators that the sub was on an infiltration mission to drop off and pick up agents.

8.   The agents are believed to have been assigned to drop into the South on an infiltration mission.

9.   The increase came amid hightened tension after a North Korean submarine ran aground on the South Korean coast on an alleged infiltration mission last month.