North-South Korean naval incidents since 1998

A file image of a June 11 1999 confrontation between South Korea (background) and North Korean (front) naval vessels in the Yellow Sea

SEOUL, South Korea -- North and South Korea are once again embroiled in a potentially explosive row, sparked by a naval clash that occurred off the west coast of the Korean Peninsula, a disputed zone in the Yellow Sea.

There is a danger the conflict could escalate between the two rivals. North and South Korea have been divided since the 1950-53 Korean War and remain technically at war never having signed a peace treaty.

When the Korean War ended in an armistice in 1953, the U.N. Command established the Northern Limit Line, a demarcation on the West Sea, to avoid clashes at sea.

But North Korea rejected it during the armistice negotiations, claiming a zone of 12 nautical miles instead of the 3 nautical miles set by the U.N.

MORE STORIES • S. Korean ship sunk in North gunbattle    AUDIO The navy battle is the most serious border clash in three years, CNN Seoul Bureau Chief Sohn Jie-Ae reports. 1.28MB / 1 min 28 secs WAV sound

As a result, the communist North does not observe the line, often sending fishing boats and naval ships into the zone.

This has caused a number of naval incidents throughout the years, despite South Korean President Kim Dae-jung having implemented a policy of reconciliation with the communist North.

The following is a chronology of major naval incidents since President Kim took office in early 1998.

June 22, 1998 -- Nine North Korean commandos found dead aboard a mini-sub caught in fishing nets, off Sokcho on the east coat of South Korea.

July 12, 1998 -- One North Korean frogman found dead on a beach at Donghae on South Korea's east coast.

November 20, 1998 -- The South Korean navy fires warning shots before chasing a North Korean spy vessel back across the maritime border near Kanghwa-do, northwest of the capital Seoul.

December 18, 1998 -- The South Korean navy sinks submersible North Korean spy vessel, with one frogman found dead in the Sea of Japan east of the Korean peninsula.

June 15, 1999 -- At least 17 (some reports said as many as 80) North Korean sailors killed after naval firefight in which one of the North's vessels was sunk and others damaged.

The clash followed nine consecutive days of North Korean incursions into South Korean waters.

June 29, 2002 -- A violent skirmish between the Koreas navies on the Yellow Sea leaves at least four South Korean sailors dead and at least 19 others injured.

North Korea has not released any casualty figures but admitted it had suffered casualties.