South Korea begins largest anti-submarine drills ever, despite North Korea threats

South Korea has 4,500 service members from all military branches engaged in five days of antisubmarine drills. North Korea has threatened to retaliate.

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South Korea began a five-day naval exercise Thursday near its disputed maritime border with North Korea in spite of the North's warnings of retaliation.

With 4,500 service members from all four branches of the military, this drill reportedly represents the nation’s largest antisubmarine training exercise ever. It is unusual for South Korea to independently conduct exercises of this scope without the involvement of the United States military.

The maneuvers are taking place off the peninsula's west coast where the South Korean warship the Cheonan was sunk in March, killing 46 sailors. A five-nation investigative team concluded in May that a torpedo fired from a North Korean submarine was responsible for the disaster, but so far the North has denied any involvement and refuses to apologize.

With tensions between the North and South steadily rising, the naval exercises represent a show of force that the South hopes will deter any military incursions from the North. The message appears to have resonated with the North, which called the training maneuvers a “direct military invasion” that infringed on the Communist nation’s “right to self-defense,” reports the BBC.

Coming less than two weeks after the South's Navy and Air Force conducted joint training exercises with the US off the peninsula's east coast, South Korean officials say that the current training exercise is purely defensive. They have dismissed threats from the North, which has warned of “powerful physical retaliation,” reports China’s state-run Xinhua news agency.

“The focus of the exercises is to strengthen our response to the enemy's asymmetric provocations and also our joint operations capabilities,” an official from the South Korea's Joint Chiefs of Staff told the Yonhap news agency. “We will not tolerate any kind of provocations by the enemy, and the drills will allow us to be fully prepared for combat.”

The drills will take place near the Northern Limit Line that acts as the maritime border for the North and the South. It was established by the United Nations after the Korean War ended in 1953, but Pyongyang has refused to accept it, arguing that the line was drawn too far north, reports Russia’s RTT News.

Although the military will conduct live fire drills over the course of the next five days, military officials have stressed that all guns will be fired south, away from the Northern Limit Line.

“The drills will be staged within our areas of operation in the West Sea. They will be staged on the ground, at sea and in the air,” said Rear Adm. Kim Kyung-sik, the JCS's chief of operations, in an article in Korea’s Chosun Ilbo newspaper.

Meanwhile, China has expressed concern over the mounting tension on the Korean Peninsula, urging both sides to find a peaceful solution. With the current drills taking place so close to China in the Yellow Sea, the developing world superpower has expressed discomfort with the drills. China’s military announced that it will also be conducting five days of defensive naval training that it says are unrelated, but analysts say there is a connection.

“China says the two are not related, but of course they are," Lee Jong-min, dean of the Graduate School of International Studies at Yonsei University, told The Christian Science Monitor. “They are asserting their military powers," he adds.

China remains essential to containing the North Korean threat, say security analysts, and its support for new US sanctions on North Korea is "critical" to their efficacy, US special adviser for nonproliferation Robert Einhorn said Monday.