The military views North Korea's shelling of waters near the Northern Limit Line on Wednesday as an intentional provocation with multiple aims. A high ranking military officer said, "It seems to be a warning message prior to South Korea-U.S. annual drills that start on Aug. 16, and a way to test how the South reacts to such provocation."

This assessment is based on the North's past patterns of provocations, as North Korea has often carried out similar provocations before the annual joint exercises. This year's provocation was not as strong as in previous years.

The North recently warned South Korea that carrying out of the drills will negate any efforts to improve inter-Korean relations. One year ago, on Aug. 9, 2010, North Korea fired over 130 artillery shells at Baeknyeong and Yeonpyeong Islands before the drill.

Fishing boats are anchored in Yeonpyeong Island as North Korea’s shelling of waters near the Northern Limit Line stopped work in the West Sea on Wednesday. /Courtesy of Yeonpyeong Island resident Kim Young-sik

What was distinctive about Wednesday's shelling is that it happened late at night despite sea fog that restricted visibility to just 1 km. Normally, artillery drills take place during the day when the weather is clear so that it is easy to check whether the shells reached their target.

"This clearly shows that it was not purely a regular military drill, but that North Korea carried it out with the intention of provoking the South," a military source said. Some believe that the North also wanted to see how the South Korean marine corps newly reacts to provocations after it was streamlined in June.

North Korean leader Kim Jong-il and his heir apparent Jong-un visited the Navy Command in Pyongyang last month, for the first time since a naval skirmish in 2002. However, the South Korean government and military believe it is less likely the North will take massive military action that would cast a chill over the current situation, where dialogue between North Korea and the U.S. has finally resumed after a long stalemate and the communist country is trying to get food and cement from the U.S.