The United States has condemned what it termed North Korea's "armed provocation" against South Korea after a naval clash that killed four South Korean sailors and wounded 19 others.
"We regret the loss of life and injuries and we want to express our sympathy for the families," said State Department spokeswoman Brenda Greenberg. "We support the stance of our ally against armed provocation," Greenberg said.
South Korean officials said North Korean vessels intruded across their disputed maritime border and fired on its boats. North Korean officials said it was the other way around, accusing the South of a "grave provocation."
One South Korean vessel was sunk in the exchange in the Yellow Sea, off the west coast of the divided peninsula.
The naval encounter was the most serious incident on the seas near the Korean peninsula in three years. It is a setback to recent efforts at reconciliation between the south and the north.
