Korea naval exercise starts despite North's protests

South Korea’s military says that it has not detected any unusual activities over the border after Pyongyang’s threats that its army and people would “legitimately counter [the exercises] with their powerful nuclear deterrence”.

Washington dubbed the North’s declarations provocative.

"We are not interested in a war of words with North Korea," said State Department official Philip Crowley. "What we need from North Korea is fewer provocative words and more constructive action."

The manoeuvres are designed to discourage the North’s “aggressive behaviour”, the US and South Korea say. They follow the sinking of the Cheonan warship, which Washington and Seoul blame on Pyongyang, which in turn denies responsibility.

They have been relocated from the Yellow – or West – Sea because of Chinese protests, South Korea’s defence ministry says, but it insists that future drills will take place in both seas.