North Korea said on Wednesday it would close its land border with the South from December 1, accusing its neighbor of taking confrontation "beyond the danger level."
It adds to the increasingly angry rhetoric by the North since South Korea's conservative government took office earlier this year with a promise to get tough over Pyongyang's nuclear weapons program.
The following is a list of military conflict and incidents that have raised tensions between the two states, that have not signed a peace treaty to formally end the 1950-53 Korean War.
* June 25, 1950: North Korean troops invade the South in an attempt to forcibly reunite the country. Chinese troops later join them to oppose U.S.-led United Nations forces. The Korean War ends with a truce signed on July 27, 1953, but the two Koreas remain technically at war.
* Aug 15, 1974: North Korean agent attempts to assassinate South Korean President Park Chung-hee in Seoul. They kill the first lady.
* October 9, 1983: More than 20 people, including four South Korean cabinet ministers, are killed in Burma (now Myanmar) when North Korean agents blow up a major landmark just minutes before South Korean President Chun Doo Hwan is due to arrive.
* November 29, 1987: North Korean agents blow up a South Korean civilian airliner, killing 115 people, leading Washington to place North Korea on its list of countries supporting terrorism.
* April 1996: North Korea renounces the armistice and sends troops into the Demilitarized Zone (DMZ) separating the two. In September, a North Korean submarine runs aground and is abandoned off the South Korean coast. Twenty-four crew are shot dead, one is captured and one escapes. Eleven of the crew are believed to have died in group suicide.
* June 15, 1999: At least 17 and as many as 80 North Korean sailors killed in first Yellow Sea clash since end of Korean War.
* June 29, 2002: Clash between South and North Korean naval vessels in the Yellow Sea sinks one South Korean frigate and kills six South Korean sailors and an estimated 13 North Koreans.
* Oct 9, 2006: First nuclear test by the North. United Nations passes sanctions banning trade in weapons and other goods with North Korea.
* May 28, 2008: North Korea test fires a battery of short-range missiles one day after it expels South Korean officials from a joint industrial complex north of the border.
* Aug 3, 2008 - Pyongyang says it will expel "unnecessary" South Korean staff from a mountain resort in the North. The move followed the killing of a South Korean tourist the previous month.
(Writing by Gillian Murdoch, Beijing Editorial Reference Unit; Editing by Jonathan Thatcher)