There were exchange of fire between North and South Korea at the disputed western sea border.
Earlier, North Korea had announced that it would hold live-fire drills in seven parts of the border area.
South Korean army who were in absolute alert returned fire when North Korean shells landed in its territorial waters.
The area has been a controversial location between the two Koreas. The UN had put-forth a line of control along the western border after the Korean War. But North Korea yet to recognize it.

Video on North and South Korea fire exchange