South Korea has begun a huge naval exercise off its west coast in response to the sinking of a warship that is blamed on North Korea.
The BBC reports the manoeuvres will last for five days and will involve 29 ships, 50 aircraft and more than 4000 personnel.
Seoul says a North Korean torpedo sank the Cheonan, but Pyongyang denies this and says the drills are a provocation.
Forty-six South Korean sailors were killed when the Cheonan went down in the Yellow Sea on 26 March.
Although the Ministry of Defence says the ships will stay clear of the disputed west coast sea boundary, live-fire exercises will be conducted by marines stationed on islands close to the border.
But military officials said that the guns would face south. They describe the exercises as "defensive" in nature.