South Korea on Friday commemorated the second anniversary of North Korea's shelling of Yeonpyeong Island near the tensely guarded western sea, as it prepared to conduct military drills to prepare for future attacks.

North Korea lobbed 170 rounds of artillery onto the front-line island two years ago, killing two Marines and two civilians in the first attack on South Korean soil since the end of the 1950-53 Korean War.

About 4,000 people, including bereaved family members, government officials and Navy officers, gathered at the War Memorial in Seoul to pay tribute to those killed in the unprovoked attack.

"The Yeonpyeong shelling is the worst provocation by North Korea since the two sides signed a truce in 1953," Prime Minister Kim Hwang-sik said in an address. "It was a violent act that directly attacked our territory, and reckless brutality that did not discriminate between soldiers and civilians."

Kim said the attack was an incident that clearly reminds all that the country is "still at war," and vowed to deter any further provocations by the North.

His remark was in line with President Lee Myung-bak's unprecedented visit to the front-line island last month, during which he said his military would launch a counterattack if there was another provocation.

"The government's determination is stronger than ever," Kim said. "President Lee's visit to Yeonpyeong Island last month was an expression of such determination."

Despite the loss of two of their own and two civilians on the island, the Marines believe they won the battle because they fired dozens of shots back at North Korean artillery bases just minutes after first being hit. The extent of damage in North Korea has never been confirmed.

Pyongyang, however, claimed it won the battle in a "victory of justice" over "injustice."

On Friday, the Rodong Shinmun, a propaganda mouthpiece for the North's ruling party, carried an editorial that claimed there were no casualties on its side and its military will "never miss the chance" to attack if the South provokes.

The North has claimed the artillery bombardment was self-defense against a live-fire drill by the South, which, it claimed, resulted in shells falling on its side of the sea border.

Troops of the two Koreas are heavily stationed near the western sea border, known as the Northern Limit Line or NLL. Pyongyang does not recognize the line and demands it be drawn further south.

Later in the day, South Korea will conduct simulated and field drills on western border islands under various scenarios of North Korean attacks. The maneuvers will involve the Marine Corps, the Navy and the Air Force, but will not include live-fire artillery exercises, the Joint Chiefs of Staff said. (Yonhap News)