BEIJING -- South Korea launched Monday a firing drill from a disputed western border island shelled last month by the Democratic People's Republic of Korea (DPRK) despite the latter's repeated warnings of a counterattack.

The followings are some major events in the Korean Peninsula this year.

-- March 26, a 1,200-ton South Korean warship Cheonan with 104 crew members onboard sank into waters off the west coast of the Korean Peninsula Friday night local time, after an explosion ripped the rear part of the ship.

-- May 20, a multinational team of investigators announced their findings, saying Cheonan was torpedoed by a DPRK submarine.

-- July 21, top diplomats and defense officials from South Korea and the United States held the so-called "two plus two" security talks, the first of its kind, to reaffirm their military alliance amid heightened tension on the Korean Peninsula.

-- September 28, the Conference of the DPRK's ruling Workers' Party of Korea (WPK) was held in Pyongyang. The conference made three major decisions, including the reelection of Kim Jong Il as general secretary of the WPK, the revision of the WPK Charter and the election of a new central leadership of the WPK.

-- September 29, South Korea's defense ministry said the DPRK agreed to hold working-level military talks with the South, the first such talks in nearly two years.

-- November 16, South Korea announced it would stage a large-scale annual military drill, code-named "Hoguk Exercise", on November 22-30 in areas including the Seoul metropolitan area and waters off the country's west coast.

-- November 23, one South Korean soldier was killed and 13 others were injured when the DPRK fired scores of artillery shells onto the South Korean-held island of Yeonpyeong near the two countries' disputed maritime border off the west coast of the peninsula. The South fired back and put its armed forces on a heightened alert.

-- November 24, the DPRK defended the shelling, saying it was in response to South Korea's military drills in waters off the peninsula's west coast, which were claimed by the DPRK.

-- November 28-December 1, South Korea and the United States staged large-scale military exercises in the Yellow Sea.

-- December 6-12, South Korea conducted a live-fire artillery drill at 29 sites in waters surrounding the country, which did not include Yeonpyeong Island. The maritime drill resumed on December 13-17 at 27 sites.

-- December 16, US New Mexico Governor Bill Richardson arrived in Pyongyang to discuss the situation on the peninsula with DPRK officials. On the same day, South Korea announced it would conduct a live-fire artillery drill on Yeonpyeong Island, located in waters claimed by the DPRK, on a certain day between December 18 and December 21.