Shots fired in Korea border dispute
South Korea's navy has fired warning shots after a North Korean naval ship briefly crossed a disputed border in the Yellow Sea, the South's Joint Chiefs of Staff say.
No casualties were reported in the third incident this year in which South Korea has fired warning shots to repel North Korean military vessels from waters near the site of deadly naval gun battles in 2002 and in 1999.
A North Korean patrol boat entered the South's waters shortly after midday and returned to the North four minutes later after five warning shots were fired, said a spokesman for the Joint Chiefs of Staff.
South Korean authorities are investigating the cause of the incursion across the so-called Northern Limit Line (NLL) boundary, adding there were no provocative moves by the North Korean navy.
There were about 10 Chinese fishing boats in the area at the time of the incident.
Tensions have been high on the Korean peninsula since October 2002, when the United States said the communist North had said it was pursuing a secret nuclear arms programme.
Monday's incident comes as preparations are being made for nuclear talks involving the two Koreas, the United States, China, Japan and Russia. The talks are expected to be held in Beijing next month.
The Northern Limit Line is the de facto sea border, drawn by U.S.-led United Nations forces when the 1950-53 Korean war ended in an armed truce. North Korea has demanded a new sea frontier be drawn far to the south and in 1999 declared the NLL invalid.