The U.S. and South Korean militaries will stage their second joint exercise in less than a month from Monday, fuelling tensions with the North and angering regional power China.
The annual exercise comes a week after Seoul completed its own drills near a disputed maritime border off the west coast that prompted the North to retaliate by firing a barrage of artillery shells in the same area.
Responding with the same rhetoric as it has in the past, the reclusive North said the latest exercise was a "dangerous act to light the fuse of a new war".
Unlike the show-of-force drills in July which involved a U.S. aircraft carrier, this month's exercises are lower key.
Washington and South Korea say the exercises are designed to intimidate to Pyongyang over ny "aggressive behaviour".
Last week's tit-for-tat military actions occurred near the Northern Limit Line, the site of several deadly clashes since the 1950-53 Korean war, and the location of the torpedoing of a South Korean warship earlier this year.
Seoul blames the sinking of the Cheonan corvette, which cost 46 lives, on Pyongyang. The North denies responsibility.
"Taking into consideration the exceptionally tense security situation following the Cheonan attack, the (latest) drills this year will be conducted throughout the whole country so that it is as similar as possible to actual battle," the South's defence ministry said.
The exercises have also sparked regional tensions, with the North's only major ally China calling the U.S.-led drills a threat to both its security and regional stability.
Following last month's U.S.-South Korea joint naval drill in the Sea of Japan off the Korean peninsula, China conducted its own heavily publicised military exercises.