North Korea on Thursday fired two artillery shells near a South Korean warship that was on a patrol mission in the tensely-guarded western sea, the Joint Chiefs of Staff (JCS) said Thursday.
The North Korean shells fell in waters 14 kilometers south of Yeonpyeong Island in the Yellow Sea, prompting a South Korean Navy corvette patrolling near the area to fire five shells into North Korean waters in return, the JCS said.
Following the incident, fishing boats operating in nearby waters were ordered to return to nearby ports and residents in Yeonpyeong Island were evacuated to shelters, officials said.
"The South Korean military is closely watching the North Korean military and preparing against additional provocations," the JCS said, adding that it is looking into the North's motivation for the firing.
The North is believed to have fired the shells with coastal artillery, military officials said.
The latest incident took place after three North Korean military vessels on Tuesday briefly crossed the Northern Limit Line, the de-facto western maritime border, prompting the South Korean military to fire warning shots to force their retreat. One day later, Pyongyang threatened to directly target South Korean warships.
The maritime border is a flash point where navies of the two sides fought bloody battles in 1999, 2002 and 2009.
In 2010, the North torpedoed a South Korean warship in the area and shelled Yeonpyeong Island, killing a total of 50 South Koreans. (Yonhap)