Largest Joint Military Exercise By The U.S. & South Korea

The way U.S. officials see it, there's little mystery behind the most notorious shipwreck in recent Korean history.

Secretary of State Hillary Rodham Clinton calls the evidence 'overwhelming' that the Cheonan, a South Korean warship that sank in March, was hit by a North Korean torpedo. Vice President Joe Biden has cited the South Korean-led panel investigating the sinking as a model of transparency.

The largest joint military exercise by the United States and South Korea in years is underway in the Sea of Japan. These war games were called in response to North Korea's sinking of the South Korean navy ship, Cheonan, an incident that killed 46 sailors in March.

About 200 aircraft are participating in the four-day drill, known as Invincible Spirit. Some took part in live fire exercises. For the first time, an exercise here also includes four of the U.S. Air Force's most advanced fighters, F_22 Raptors.The emphasis is on antisubmarine warfare with ships and planes looking for dummy targets similar to the midget submarine that an investigation, led by South Korea and including experts from the US, Britain, Australia, and Sweden, concluded had fired the torpedo that split the Cheonan in two. North Korea continues to deny any role in the attack, in which 46 sailors were killed, but has said it wants to talk about it with investigators.


North Korea's threat to unleash a nuclear attack in response to the joint war games, Commander Walczak says, is not causing undue alarm for the U.S. 7th Fleet

Rear Admiral Dan Cloyd says that the current exercise, "purely defensive in nature" and says there's no reason for North Korea to be provocative.He also said that their intent is to improve defense capabilities in areas such as anti-submarine warfare, air defense and anti-surface warfare.

North Korea denies responsibility for the sinking of the Cheonan in the Yellow Sea on March 26. The incident has escalated tension on the Korean peninsula, which, on Tuesday, marks the 57th anniversary of the armistice that halted the Korean War. The two sides have yet to sign a peace treaty.

Choi predicts “they will try to conduct a nuclear test or a missile test” but notes the North faces severe internal problems. North Korea's reclusive leader Kim Jong-il, suffering from a variety of illnesses, is attempting to put on an appearance of strength while preparing for his third son, Kim Jong-eun, to take over when he leaves the scene