Seoul: US and South Korean warships and helicopters practiced anti-submarine manoeuvres off the Korean peninsula on Monday, readying defences against the kind of weapon that allegedly sank a South Korean Navy vessel earlier this year.
The destruction of the Cheonan in March, which has been blamed on a North Korean torpedo, killed 46 sailors in what officials called the worst military attack on the South since the 1950-53 Korean War.
The four-day "Invincible Spirit" exercises involving 20 ships, 200 aircraft and about 8,000 US and South Korean sailors are being held in the waters off Korea`s east coast in response to the sinking, bringing threats of retaliation from North Korea, which denies responsibility for the attack.
The anti-submarine phase of the training — which also involves anti-ship and anti-aircraft operations — is particularly important because an international investigation found that the 1,200-ton corvette Cheonan was sunk by a torpedo launched from a North Korean submarine that somehow penetrated South Korea`s defences.
"I am concerned about every submarine underwater that I don`t know about," said Capt David Lausman, the commanding officer of the USS George Washington, a nuclear-powered supercarrier deployed to the manoeuvres from its home port in Japan.
Lausman said the attack demonstrated the opaque nature of Pyongyang`s military, which he said should not be underestimated.
"North Korea`s danger lies because they are unpredictable," he said. "The sinking of the Cheonan is a prime example."
North Korea has strongly protested the exercises, saying they are a provocation and threatening retaliation. In flourishes of rhetoric typical of the regime, it vowed to respond with a "sacred war" and a "powerful nuclear deterrence”.
"They will face a costly consequence if they stick to the criminal activities ravaging peace and security on the Korean peninsula," North Korea`s main Rodong Sinmun newspaper said in commentary carried by the official Korean Central News Agency.
US officials say that the manoeuvres, held well away from North Korea`s border, are not intended to provoke a response, but add that they do want to send Pyongyang a message that further aggression in the region will not be tolerated and that the alliance between the US and South Korea remains strong.
On Monday, Gen Han Min-goo, chief of the South Korean Joint Chiefs of Staff, was to tour the George Washington.
The exercises are the first in a series of US-South Korean manoeuvres conducted in the East Sea off Korea and in the Yellow Sea closer to China`s shores in international waters.
They are the first to employ the F-22 stealth fighter — which can evade North Korean air defences — in South Korea.
The North routinely threatens attacks whenever South Korea and the US hold joint military drills, which Pyongyang sees as a rehearsal for an invasion. The US keeps 28,500 troops in South Korea and another 50,000 in Japan, but says it has no intention of invading the North.