South Korea says it plans to hold a military exercise near the tense sea border with North Korea on Wednesday to mark the one-year anniversary of North's deadly artillery attack on the border island of Yeongpyeong.

The South Korean military says it will conduct land, sea and air exercises to simulate a response to a hypothetical North Korean bombardment and invasion of the island.

One year ago, two marines and two civilians were killed when the North launched an attack during a South Korean artillery exercise on Yeongpyeong island, which is located near the two countries' disputed border on the Yellow Sea.

Seoul also blames Pyongyang for the sinking of the warship Cheonan in March last year, which killed 46 seamen.

The latest drill comes at a time of slowly easing tensions with North Korea, which routinely denounces such military exercises as rehearsals for an invasion of the North.

The South, which has been criticized by some for responding passively to the Yeonpyoeng shelling, has vowed to strike back “sternly” at any future attack from the North.