July 17 -- South and North Korean soldiers exchange machine gun fire along their border, but no casualties on South Korean side. Unclear whether any North Korean troops were injured or killed.
March 2 -- Four North Korean fighter jets intercept a U.S. Air Force RC-135 reconnaissance plane off North Korea's east coast. The U.S. plane leaves the area.
Feb. 20 -- A North Korean MiG-29 fighter jet crosses the western sea border with South Korea but retreats two minutes later when met by two Southern jets.
June 29, 2002 -- A North Korean navy boat crosses the maritime border and sinks a Southern patrol boat. Six South Korean sailors die, North Korean toll in shootout is unknown.
Nov. 27, 2001 -- North and South Korean soldiers exchange gunfire inside the Demilitarized Zone. No reports of casualties or injuries.
June 15, 1999-- A series of border violations by North Korean ships touch off the first naval clash between the two Koreas since the Korean War. One North Korean warship sinks and about 30 North Korean sailors die, according to South Korea. Several South Korean sailors are wounded.