North Korea has threatened to fire on South Korean Navy vessels it says are trespassing in its waters.
 
The North's official Korean Central News Agency on Friday quoted an emergency warning from the North's Southwestern Frontline Command which said South Korean Navy speedboats have been crossing the maritime border in the Yellow Sea around Baengnyeong Island two to three times a day, vowing fire on them without warning
 
It is unclear, however, whether the maritime border refers to the Northern Limit Line established by the United Nations Command or the West Sea border unilaterally claimed by the North in December 2007.
 
The North said 17 South Korean Navy speedboats had trespassed in its waters between May 1 and 7 and five speedboats crossed into its waters on April 26.