SEOUL, South Korea (AP) - South Korea's troops are on high alert for possible retaliation by North Korea.

A clash between two navy ships yesterday left a vessel from the North nearly destroyed and an officer reportedly killed.

The skirmish happened on the disputed western sea border. It was the first such engagement in seven years.

The confrontation has sent tensions soaring about a week before President Barack Obama travels to South Korea as part of his Asian tour.

Secretary of State Hillary Rodham Clinton says the situation won't disrupt diplomatic efforts to resolve the nuclear standoff with the North.

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