TIMELINE: Major incidents along border of rival Koreas

SEOUL (Reuters) - North Korea increased regional tension just ahead of a trip to Asia this week by U.S. President Barack Obama by sparking a small-scale naval skirmish with the South on Tuesday.

The following is a list of major border incidents since 1998, when the then South Korean President Kim Dae-jung articulated his "Sunshine Policy" of engagement with the North:

December 18, 1998 - South Korean navy sinks submersible North Korean spy vessel on east coast. A scuba diver from the North is found dead.

June 1999 - At least 17 and as many as 80 North Korean sailors killed in naval firefight over Northern Limit Line (NLL), a west coast, Yellow Sea border contested by the North. One of the North's vessels was sunk, others damaged.

Clash followed nine days of incursions by the North into South Korean waters.

November 27, 2001 - North Korean soldiers fire at a South Korean guard post and South returns fire.

June 29, 2002 - A clash between South and North Korean naval vessels in Yellow Sea sinks one South Korean frigate and kills six South Korean sailors and an estimated 13 North Koreans.

July 17, 2003 - South Korea says its troops returned machinegun fire a minute after the North shot at an observation post in the Demilitarized Zone (DMZ) buffer between the states.

July 14, 2004 - A South Korean navy ship fires two warning shots at a North Korean patrol boat near the NLL.

November 1 - South Korean patrol boats fire warning shots to repel three North Korean patrol boats that cross the NLL.

April 23, 2005 - Pyongyang says the South Korean military fired a gunshot at a North Korean border guard post.

May 26, 2006 - Two North Korean soldiers enter DMZ and cross into South Korea. They return after South fires warning shots.

Oct 7, 2006 - South Korea fires warning shots after North Korean soldiers cross briefly into their side of the border.

July 11, 2008 - South Korean tourist, a 53-year-old housewife, shot dead by North Korean soldier at the Mount Kumgang resort in the North, which is run by companies in the South.

November 10, 2009 - Two Koreas have brief naval fight just south of the NLL.

(Reporting by Jon Herskovitz; Editing by David Fox)