SEOUL In the most serious such confrontation since last year's Pyongyang Summit, the South Korean Navy fired warning shots Sunday to see off a North Korean fishing boat in southern waters. The fishing vessel's presumed crew of five ignored initial warning signals after entering South Korean waters, the Seoul Defense Ministry said, and crossed back only after warning shots.

It was the most serious border incident since the summit 12 months ago of South and North Korean leaders in the North Korean capital brought a thaw in relations.