Military on alert amid shelling sounds across sea border

The South Korean military is closely watching movements of North Korean forces after detecting frequent shelling sounds across the Northern Limit Line, the imaginary inter-Korean sea border in the Yellow Sea.

A high-ranking source of the South Korean military said Thursday that frequent artillery shelling sounds were heard and presumed to be coming from the North`s long-range guns and rocket launchers deployed in inland areas near the South`s northwestern frontline islands.

"The North Korean military seems to be briskly conducting winter military drills more than previous years after a hiatus following the death of North Korean leader Kim Jong Il," the source said. "The (South Korean) military is on alert as the North is concentrating on artillery firing drills."

South Korea is said to be closely watching movements by the North Korean artillery troops concentrated in areas near the North`s west coast via a high-performance video surveillance system and the hostile artillery locating system, which were deployed on Baengnyeong and Yeonpyeong islands after the North`s shelling of Yeonpyeong in December 2010.

In addition, Seoul confirmed that Pyongyang recently completed construction of a large base for hovercrafts at Goampo in Hwanghae Province near the sea border. The South Korean military said the Goampo base has a ground mooring facility built with high-strength concrete and can accommodate about 70 hovercraft units simultaneously.

"After analyzing recent satellite pictures, we concluded that North Korea has completed the Goampo base," a South Korean government source said. "The Northwest Islands Defense Command is drawing up an operational plan to defend against a potential surprise infiltration on hovercrafts by the North."

While operating vessels or hovercraft could be impossible because waters off the Goampo coast are frozen, Seoul will keep a close eye since Pyongyang might deploy hovercraft to the Goampo base once the weather gets warmer.

The Goampo base is about 50 kilometers away from the South`s frontline islands, including Baengnyeong. North Korea plans to send hovercraft carrying special forces to infiltrate areas south of the sea border to occupy the frontline islands within 40 to 50 minutes.

North Korea has two types of hovercraft: the 35 ton-class Gongbang II, which is 21 meters long with a maximum speed of 74 kilometers per hour, and the 20 ton-class Gongbang-III, which is 18 meters long with a maximum speed of 96 kilometers per hour. Each hovercraft can carry a platoon. The North`s 170 ton-class combat hovercraft is 34 meters long and can reach a speed of up to 83 kilometers per hour. Equipped with 57- and 30-millimeter machine guns, it can infiltrate company-size special forces.

South Korean military authorities have been preparing for hovercraft infiltration by conducing two firing drills by Cobra attack choppers on Baengnyeong Island.

ysh1005@donga.com